Insulin Like Growth Factor 2 Expression in the Rat Brain Both in Basal Condition and following Learning Predominantly Derives from the Maternal Allele.

Directory of Open Access Journals (Sweden)

Xiaojing Ye

Full Text Available Insulin like growth factor 2 (Igf2 is known as a maternally imprinted gene involved in growth and development. Recently, Igf2 was found to also be regulated and required in the adult rat hippocampus for long-term memory formation, raising the question of its allelic regulation in adult brain regions following experience and in cognitive processes. We show that, in adult rats, Igf2 is abundantly expressed in brain regions involved in cognitive functions, like hippocampus and prefrontal cortex, compared to the peripheral tissues. In contrast to its maternal imprinting in peripheral tissues, Igf2 is mainly expressed from the maternal allele in these brain regions. The training-dependent increase in Igf2 expression derives proportionally from both parental alleles, and, hence, is mostly maternal. Thus, Igf2 parental expression in the adult rat brain does not follow the imprinting rules found in peripheral tissues, suggesting differential expression regulation and functions of imprinted genes in the brain.

Igf2/H19 Imprinting Control Region (ICR: An Insulator or a Position-Dependent Silencer?

Directory of Open Access Journals (Sweden)

Subhasis Banerjee

2001-01-01

Full Text Available The imprinting control region (ICR located far upstream of the H19 gene, in conjunction with enhancers, modulates the transcription of Igf2 and H19 genes in an allele-specific manner. On paternal inheritance, the methylated ICR silences the H19 gene and indirectly facilitates transcription from the distant Igf2 promoter, whereas on the maternal chromosome the unmethylated ICR, together with enhancers, activates transcription of the H19 gene and thereby contributes to the repression of Igf2. This repression of maternal Igf2 has recently been postulated to be due to a chromatin boundary or insulator function of the unmethylated ICR. Central to the insulator model is the site-specific binding of a ubiquitous nuclear factor CTCF which exhibits remarkable flexibility in functioning as transcriptional activator or silencer. We suggest that the ICR positioned close to the enhancers in an episomal context might function as a transcriptional silencer by virtue of interaction of CTCF with its modifiers such as SIN3A and histone deacetylases. Furthermore, a localised folded chromatin structure resulting from juxtaposition of two disparate regulatory sequences (enhancer ICR could be the mechanistic basis of ICR-mediated position-dependent (ICR-promoter transcriptional repression in transgenic Drosophila.

Effect Of IGF-1 On Expression Of Gh Receptor, IGF-1, IGF-1 ...

African Journals Online (AJOL)

... and the skin expression of growth hormone receptor (GHR), insulin-like growth factor1 (IGF-1), insulin-like growth factor receptor (IGF- R), KAP3.2 and KAP6-1 mRNA were measured by RT-PCR. The results indicated that IGF-1 could degrade GHR gene expression, have no effect of IGF-1 and IGF-1R gene expression, ...

Study on the Imprinting Status of Insulin-Like Growth Factor II (IGF-II Gene in Villus during 6–10 Gestational Weeks

Directory of Open Access Journals (Sweden)

Jianhong Chen

2010-01-01

Full Text Available Objective. To compare the difference of imprinting status of insulin-like growth factor II (IGF-II gene in villus between normal embryo development group and abnormal embryo development group and to investigate the relationship between karyotype and the imprinting status of IGF-II gene. Methods. A total of 85 pregnant women with singleton pregnancy were divided into two groups: one with abnormal embryo development (n=38 and the other with normal embryo development (n=47. Apa I polymorphism of IGF-II gene in chorionic villus was assayed with reverse transcriptase polymerase chain reaction (RT-PCR and restriction fragment length polymorphism (RFLP. The relationship between chromosomal abnormal karyotype and IGF-II gene imprinting status was analyzed by primary cell culture and G-banding chromosomal karyotype analysis. Results. IGF-II imprinting loss rate was higher in the abnormal embryo development group than the normal embryo development group (44.7% versus 31.6%, but without significant difference (P>.05. The percentage of abnormal chromosomes of chorionic villus in the abnormal embryo development group was 42.5%, in which IGF-II imprinting loss rate reached 64.7%. No abnormal karyotypes were found in the normal embryo development group. However, there was significant difference in IGF-II imprinting loss rate between two groups (P>.05. Conclusion. During weeks 6–10 of gestation, abnormal embryonic development is correlated with chromosomal abnormalities. The imprinting status of IGF-II gene played important roles in embryonic development, and imprinting loss might be related to chromosomal abnormalities.

CTCF-dependent chromatin bias constitutes transient epigenetic memory of the mother at the H19-Igf2 imprinting control region in prospermatogonia.

Directory of Open Access Journals (Sweden)

Dong-Hoon Lee

2010-11-01

Full Text Available Genomic imprints-parental allele-specific DNA methylation marks at the differentially methylated regions (DMRs of imprinted genes-are erased and reestablished in germ cells according to the individual's sex. Imprint establishment at paternally methylated germ line DMRs occurs in fetal male germ cells. In prospermatogonia, the two unmethylated alleles exhibit different rates of de novo methylation at the H19/Igf2 imprinting control region (ICR depending on parental origin. We investigated the nature of this epigenetic memory using bisulfite sequencing and allele-specific ChIP-SNuPE assays. We found that the chromatin composition in fetal germ cells was biased at the ICR between the two alleles with the maternally inherited allele exhibiting more H3K4me3 and less H3K9me3 than the paternally inherited allele. We determined genetically that the chromatin bias, and also the delayed methylation establishment in the maternal allele, depended on functional CTCF insulator binding sites in the ICR. Our data suggest that, in primordial germ cells, maternally inherited allele-specific CTCF binding sets up allele-specific chromatin differences at the ICR. The erasure of these allele-specific chromatin marks is not complete before the process of de novo methylation imprint establishment begins. CTCF-dependent allele-specific chromatin composition imposes a maternal allele-specific delay on de novo methylation imprint establishment at the H19/Igf2 ICR in prospermatogonia.

A DNMT3A2-HDAC2 Complex Is Essential for Genomic Imprinting and Genome Integrity in Mouse Oocytes

Directory of Open Access Journals (Sweden)

Pengpeng Ma

2015-11-01

Full Text Available Maternal genomic imprints are established during oogenesis. Histone deacetylases (HDACs 1 and 2 are required for oocyte development in mouse, but their role in genomic imprinting is unknown. We find that Hdac1:Hdac2−/− double-mutant growing oocytes exhibit global DNA hypomethylation and fail to establish imprinting marks for Igf2r, Peg3, and Srnpn. Global hypomethylation correlates with increased retrotransposon expression and double-strand DNA breaks. Nuclear-associated DNMT3A2 is reduced in double-mutant oocytes, and injecting these oocytes with Hdac2 partially restores DNMT3A2 nuclear staining. DNMT3A2 co-immunoprecipitates with HDAC2 in mouse embryonic stem cells. Partial loss of nuclear DNMT3A2 and HDAC2 occurs in Sin3a−/− oocytes, which exhibit decreased DNA methylation of imprinting control regions for Igf2r and Srnpn, but not Peg3. These results suggest seminal roles of HDAC1/2 in establishing maternal genomic imprints and maintaining genomic integrity in oocytes mediated in part through a SIN3A complex that interacts with DNMT3A2.

Effects of Assisted Reproduction Technology on Placental Imprinted Gene Expression

Science.gov (United States)

Katagiri, Yukiko; Aoki, Chizu; Tamaki-Ishihara, Yuko; Fukuda, Yusuke; Kitamura, Mamoru; Matsue, Yoichi; So, Akiko; Morita, Mineto

2010-01-01

We used placental tissue to compare the imprinted gene expression of IGF2, H19, KCNQ1OT1, and CDKN1C of singletons conceived via assisted reproduction technology (ART) with that of spontaneously conceived (SC) singletons. Of 989 singletons examined (ART n = 65; SC n = 924), neonatal weight was significantly lower (P < .001) in the ART group than in the SC group, but placental weight showed no significant difference. Gene expression analyzed by real-time PCR was similar for both groups with appropriate-for-date (AFD) birth weight. H19 expression was suppressed in fetal growth retardation (FGR) cases in the ART and SC groups compared with AFD cases (P < .02 and P < .05, resp.). In contrast, CDKN1C expression was suppressed in FGR cases in the ART group (P < .01), while KCNQ1OT1 expression was hyperexpressed in FGR cases in the SC group (P < .05). As imprinted gene expression patterns differed between the ART and SC groups, we speculate that ART modifies epigenetic status even though the possibilities always exist. PMID:20706653

DNA methylation modulates H19 and IGF2 expression in porcine female eye

Directory of Open Access Journals (Sweden)

Dongxu Wang

2017-03-01

Full Text Available Abstract The sexually dimorphic expression of H19/IGF2 is evolutionarily conserved. To investigate whether the expression of H19/IGF2 in the female porcine eye is sex-dependent, gene expression and methylation status were evaluated using quantitative real-time PCR (qPCR and bisulfite sequencing PCR (BSP. We hypothesized that H19/IGF2 might exhibit a different DNA methylation status in the female eye. In order to evaluate our hypothesis, parthenogenetic (PA cells were used for analysis by qPCR and BSP. Our results showed that H19 and IGF2 were over-expressed in the female eye compared with the male eye (3-fold and 2-fold, respectively. We observed a normal monoallelic methylation pattern for H19 differentially methylated regions (DMRs. Compared with H19 DMRs, IGF2 DMRs showed a different methylation pattern in the eye. Taken together, these results suggest that elevated expression of H19/IGF2 is caused by a specific chromatin structure that is regulated by the DNA methylation status of IGF2 DMRs in the female eye.

DNA methylation modulates H19 and IGF2 expression in porcine female eye

Science.gov (United States)

Wang, Dongxu; Wang, Guodong; Yang, Hao; Liu, Haibo; Li, Cuie; Li, Xiaolan; Lin, Chao; Song, Yuning; Li, Zhanjun; Liu, Dianfeng

2017-01-01

Abstract The sexually dimorphic expression of H19/IGF2 is evolutionarily conserved. To investigate whether the expression of H19/IGF2 in the female porcine eye is sex-dependent, gene expression and methylation status were evaluated using quantitative real-time PCR (qPCR) and bisulfite sequencing PCR (BSP). We hypothesized that H19/IGF2 might exhibit a different DNA methylation status in the female eye. In order to evaluate our hypothesis, parthenogenetic (PA) cells were used for analysis by qPCR and BSP. Our results showed that H19 and IGF2 were over-expressed in the female eye compared with the male eye (3-fold and 2-fold, respectively). We observed a normal monoallelic methylation pattern for H19 differentially methylated regions (DMRs). Compared with H19 DMRs, IGF2 DMRs showed a different methylation pattern in the eye. Taken together, these results suggest that elevated expression of H19/IGF2 is caused by a specific chromatin structure that is regulated by the DNA methylation status of IGF2 DMRs in the female eye. PMID:28266684

HIF2A and IGF2 Expression Correlates in Human Neuroblastoma Cells and Normal Immature Sympathetic Neuroblasts

Directory of Open Access Journals (Sweden)

Sofie Mohlin

2013-03-01

Full Text Available During normal sympathetic nervous system (SNS development, cells of the ganglionic lineage can malignantly transform and develop into the childhood tumor neuroblastoma. Hypoxia-inducible transcription factors (HIFs mediate cellular responses during normal development and are central in the adaptation to oxygen shortage. HIFs are also implicated in the progression of several cancer forms, and high HIF-2α expression correlates with disseminated disease and poor outcome in neuroblastoma. During normal SNS development, HIF2A is transiently expressed in neuroblasts and chromaffin cells. SNS cells can, during development, be distinguished by distinct gene expression patterns, and insulin-like growth factor 2 (IGF2 is a marker of sympathetic chromaffin cells, whereas sympathetic neuroblasts lack IGF2 expression. Despite the neuronal derivation of neuroblastomas, we show that neuroblastoma cell lines and specimens express IGF2 and that expression of HIF2A and IGF2 correlates, with the strongest correlation in high-stage tumors. In neuroblastoma, both IGF2 and HIF2A are hypoxia-driven and knocking down IGF2 at hypoxia resulted in downregulated HIF2A levels. HIF-2α and IGF2 were strongly expressed in subsets of immature neuroblastoma cells, suggesting that these two genes could be co-expressed also at early stages of SNS development. We show that IGF2 is indeed expressed in sympathetic chain ganglia at embryonic week 6.5, a developmental stage when HIF-2α is present. These findings provide a rationale for the unexpected IGF2 expression in neuroblastomas and might suggest that IGF2 and HIF2A positive neuroblastoma cells are arrested at an embryonic differentiation stage corresponding to the stage when sympathetic chain ganglia begins to coalesce.

Expression of IGF-I, IGF-I receptor and IGF binding proteins-1, -2, -3, -4 and -5 in human atherectomy specimens.

Science.gov (United States)

Grant, M B; Wargovich, T J; Ellis, E A; Tarnuzzer, R; Caballero, S; Estes, K; Rossing, M; Spoerri, P E; Pepine, C

1996-12-17

The molecular and cellular processes that induce rapid atherosclerotic plaque progression in patients with unstable angina and initiate restenosis following coronary interventional procedures are uncertain. We examined primary (de novo) and restenotic lesions retrieved at the time of directional coronary atherectomy for expression of insulin-like-growth factor-I (IGF-I). IGF-I receptor, and five IGF binding proteins (IGFBPs), IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 in smooth muscle cells (SMCs) using colloidal gold immunocytochemistry. IGF-1, its receptor and binding proteins were not detected in SMCs of normal coronary arteries. IGF-I localized primarily in synthetic smooth muscle cells (sSMCs) in both de novo and restenotic plaques. IGF-I receptor localized on sSMCs and their processes and colocalized with IGF-I. Although morphometric analysis of IGF-I and IGF-I receptor immunoreactivity in sSMCs of de novo and restenotic lesions showed comparable levels of IGF-I (3.2 +/- 1.0 and 2.9 +/- 0.9, respectively). IGF-I receptor was significantly higher in de novo lesions as compared to restenotic lesions (10.7 +/- 2.5 and 4.2 +/- 1.3, P system.

The effects of depression and use of antidepressive medicines during pregnancy on the methylation status of the IGF2 imprinted control regions in the offspring

Directory of Open Access Journals (Sweden)

Soubry A

2011-10-01

Full Text Available Abstract In utero exposures to environmental factors may result in persistent epigenetic modifications affecting normal development and susceptibility to chronic diseases in later life. We explored the relationship between exposure of the growing fetus to maternal depression or antidepressants and DNA methylation at two differentially methylated regions (DMRs of the imprinted Insulin-like Growth Factor 2 (IGF2 gene. Aberrant DNA methylation at the IGF2 and neighboring H19 DMRs has been associated with deregulated IGF2 expression, childhood cancers and several chronic diseases during adulthood. Our study population is comprised of pregnant mothers and their newborns (n = 436, as part of the Newborn Epigenetics Study (NEST. A standardized questionnaire was completed and medical record data were abstracted to ascertain maternal depression and antidepressive drug use. DMR methylation levels in umbilical cord blood leukocytes were quantified using pyrosequencing. From the 436 newborns, laboratory data were obtained for 356 individuals at the IGF2 DMRs, and for 411 individuals at the H19 DMRs; about half of each group was African American or Caucasian. While overall no association between depression and methylation profiles was found, we observed a significant hypermethylation of the H19 DMRs in newborns of African American (n = 177 but not Caucasian (n = 168 mothers who reported the use of antidepressive drugs during pregnancy (β = +6.89, p = 0.01. Of note, our data reveal a race-independent association between smoking during pregnancy and methylation at the IGF2 DMR (+3.05%, p = 0.01. In conclusion, our findings suggest a race-dependent response related to maternal use of antidepressants at one of the IGF2 DMRs in the offspring.

Deregulation of an imprinted gene network in prostate cancer.

Science.gov (United States)

Ribarska, Teodora; Goering, Wolfgang; Droop, Johanna; Bastian, Klaus-Marius; Ingenwerth, Marc; Schulz, Wolfgang A

2014-05-01

Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes.

Generation of Five Human Lactoferrin Transgenic Cloned Goats Using Fibroblast Cells and Their Methylation Status of Putative Differential Methylation Regions of IGF2R and H19 Imprinted Genes

Science.gov (United States)

Sun, Yanyan; Zhang, Yanli; Wang, Ziyu; Song, Yang; Wang, Feng

2013-01-01

Background Somatic cell nuclear transfer (SCNT) is a promising technique to produce transgenic cloned mammalian, including transgenic goats which may produce Human Lactoferrin (hLF). However, success percentage of SCNT is low, because of gestational and neonatal failure of transgenic embryos. According to the studies on cattle and mice, DNA methylation of some imprinted genes, which plays a vital role in the reprogramming of embryo in NT maybe an underlying mechanism. Methodology/Principal Findings Fibroblast cells were derived from the ear of a two-month-old goat. The vector expressing hLF was constructed and transfected into fibroblasts. G418 selection, EGFP expression, PCR, and cell cycle distribution were applied sequentially to select transgenic cells clones. After NT and embryo transfer, five transgenic cloned goats were obtained from 240 cloned transgenic embryos. These transgenic goats were identified by 8 microsatellites genotyping and southern blot. Of the five transgenic goats, 3 were lived after birth, while 2 were dead during gestation. We compared differential methylation regions (DMR) pattern of two paternally imprinted genes (H19 and IGF2R) of the ear tissues from the lived transgenic goats, dead transgenic goats, and control goats from natural reproduction. Hyper-methylation pattern appeared in cloned aborted goats, while methylation status was relatively normal in cloned lived goats compared with normal goats. Conclusions/Significance In this study, we generated five hLF transgenic cloned goats by SCNT. This is the first time the DNA methylation of lived and dead transgenic cloned goats was compared. The results demonstrated that the methylation status of DMRs of H19 and IGF2R were different in lived and dead transgenic goats and therefore this may be potentially used to assess the reprogramming status of transgenic cloned goats. Understanding the pattern of gene imprinting may be useful to improve cloning techniques in future. PMID:24204972

Complete biallelic insulation at the H19/Igf2 imprinting control region position results in fetal growth retardation and perinatal lethality.

Directory of Open Access Journals (Sweden)

Dong-Hoon Lee

2010-09-01

Full Text Available The H19/Igf2 imprinting control region (ICR functions as an insulator exclusively in the unmethylated maternal allele, where enhancer-blocking by CTCF protein prevents the interaction between the Igf2 promoter and the distant enhancers. DNA methylation inhibits CTCF binding in the paternal ICR allele. Two copies of the chicken β-globin insulator (ChβGI(2 are capable of substituting for the enhancer blocking function of the ICR. Insulation, however, now also occurs upon paternal inheritance, because unlike the H19 ICR, the (ChβGI(2 does not become methylated in fetal male germ cells. The (ChβGI(2 is a composite insulator, exhibiting enhancer blocking by CTCF and chromatin barrier functions by USF1 and VEZF1. We asked the question whether these barrier proteins protected the (ChβGI(2 sequences from methylation in the male germ line.We genetically dissected the ChβGI in the mouse by deleting the binding sites USF1 and VEZF1. The methylation of the mutant versus normal (ChβGI(2 significantly increased from 11% to 32% in perinatal male germ cells, suggesting that the barrier proteins did have a role in protecting the (ChβGI(2 from methylation in the male germ line. Contrary to the H19 ICR, however, the mutant (mChβGI(2 lacked the potential to attain full de novo methylation in the germ line and to maintain methylation in the paternal allele in the soma, where it consequently functioned as a biallelic insulator. Unexpectedly, a stricter enhancer blocking was achieved by CTCF alone than by a combination of the CTCF, USF1 and VEZF1 sites, illustrated by undetectable Igf2 expression upon paternal transmission.In this in vivo model, hypomethylation at the ICR position together with fetal growth retardation mimicked the human Silver-Russell syndrome. Importantly, late fetal/perinatal death occurred arguing that strict biallelic insulation at the H19/Igf2 ICR position is not tolerated in development.

Gastric cancer: the role of insulin-like growth factor 2 (IGF 2) and its receptors (IGF 1R and M6-P/IGF 2R).

Science.gov (United States)

Pavelić, Kresimir; Kolak, Toni; Kapitanović, Sanja; Radosević, Senka; Spaventi, Sime; Kruslin, Bozo; Pavelić, Jasminka

2003-11-01

Insulin-like growth factor 2 (IGF 2) appears to be involved in the progression of many tumours. It binds to at least two different types of receptor: IGF type 1 (IGF 1R) and mannose 6-phosphate/IGF type 2 (M6-P/IGF 2R). Ligand binding to IGF 1R provokes mitogenic and anti-apoptotic effects. M6-P/IGF 2R has a tumour suppressor function--it mediates IGF 2 degradation. Mutation of M6-P/IGF 2R causes both diminished growth suppression and augmented growth stimulation. The aim of this study was to investigate the role of IGF 2 and its receptors (IGF 1R and IGF 2R) in human gastric cancer. The expression of IGF 2 and its receptors was measured in order to analyse the possible correlation between the activity of these genes and cell proliferation in two different gastric tumour types: diffuse and intestinal. The effect of IGF 1 receptor blockage on cell proliferation and anchorage-independent cell growth was also examined. Increased expression of IGF 2 and IGF 1R genes (at the mRNA and protein level) was found in gastric cancer when compared with non-tumour tissue. Furthermore, there was a significant difference between IGF 2 expression in the more aggressive diffuse type and that in the intestinal type of gastric cancer. Moreover, the IGF 2 peptide level in the culture media obtained from the diffuse type of cancer cells was significantly higher when compared with the intestinal type. The level of IGF 2 peptide in the conditioned media strongly correlated with [3H]thymidine incorporation and cell proliferation. On the contrary, IGF 2R mRNA expression was much higher in the intestinal type of cancer than in the diffuse type. In addition, IGF 2R protein expression was substantially lower with progression of the diffuse cancer type to a higher stage. The alphaIR3 monoclonal antibody strongly inhibited [3H]thymidine incorporation and decreased the number of colonies in soft agar of cells overexpressing IGF 2. These findings suggest that members of the IGF family are involved

Loss of imprinting and loss of heterozygosity on 11p15.5 in head and neck squamous cell carcinomas

DEFF Research Database (Denmark)

Rainho, C A; Kowalski, L P; Rogatto, S R

2001-01-01

BACKGROUND: IGF2 and H19 are reciprocal imprinted genes with paternal and maternal monoallelic expression, respectively. This is interesting, because IGF2 is known as a growth factor, and H19 encodes a RNA with putative tumor suppressor action. Furthermore, IGF2 and H19 are linked genes located...

Butyrate induced IGF2 activation correlated with distinct chromatin landscapes due to histone modification

Science.gov (United States)

Histone modification has emerged as a very important mechanism regulating the transcriptional status of the genome. Insulin-like growth factor 2 (IGF2) is a peptide hormone controlling various cellular processes such as proliferation and apoptosis. IGF2 and H19 are reciprocally regulated imprinted ...

Embryonic IGF2 expression is not associated with offspring size among populations of a placental fish.

Directory of Open Access Journals (Sweden)

Matthew Schrader

Full Text Available In organisms that provision young between fertilization and birth, mothers and their developing embryos are expected to be in conflict over embryonic growth. In mammalian embryos, the expression of Insulin-like growth factor II (IGF2 plays a key role in maternal-fetal interactions and is thought to be a focus of maternal-fetal conflict. Recent studies have suggested that IGF2 is also a focus of maternal-fetal conflict in placental fish in the family Poeciliidae. However, whether the expression of IGF2 influences offspring size, the trait over which mothers and embryos are likely to be in conflict, has not been assessed in a poeciliid. We tested whether embryonic IGF2 expression varied among four populations of a placental poeciliid that display large and consistent differences in offspring size at birth. We found that IGF2 expression varied significantly among embryonic stages with expression being 50% higher in early stage embryos than late stage embryos. There were no significant differences among populations in IGF2 expression; small differences in expression between population pairs with different offspring sizes were comparable in magnitude to those between population pairs with the same offspring sizes. Our results indicate that variation in IGF2 transcript abundance does not contribute to differences in offspring size among H. formosa populations.

Characterization of the imprinting and expression patterns of ZAG2 in maize endosperm and embryo

Directory of Open Access Journals (Sweden)

Chaoxian Liu

2015-02-01

Full Text Available ZAG2 has been identified as a maternally expressed imprinted gene in maize endosperm. Our study revealed that paternally inherited ZAG2 alleles were imprinted in maize endosperm and embryo at 14 days after pollination (DAP, and consistently imprinted in endosperm at 10, 12, 16, 18, 20, 22, 24, 26, and 28 DAP in reciprocal crosses between B73 and Mo17. ZAG2 alleles were also imprinted in reciprocal crosses between Zheng 58 and Chang 7-2 and between Huang C and 178. ZAG2 alleles exhibited differential imprinting in hybrids of 178 × Huang C and B73 × Mo17, while in other hybrids ZAG2 alleles exhibited binary imprinting. The tissue-specific expression pattern of ZAG2 showed that ZAG2 was expressed at a high level in immature ears, suggesting that ZAG2 plays important roles in not only kernel but ear development.

Biochemical characterization of individual human glycosylated pro-insulin-like growth factor (IGF)-II and big-IGF-II isoforms associated with cancer.

Science.gov (United States)

Greenall, Sameer A; Bentley, John D; Pearce, Lesley A; Scoble, Judith A; Sparrow, Lindsay G; Bartone, Nicola A; Xiao, Xiaowen; Baxter, Robert C; Cosgrove, Leah J; Adams, Timothy E

2013-01-04

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed "pro" and "big" IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling.

Biochemical Characterization of Individual Human Glycosylated pro-Insulin-like Growth Factor (IGF)-II and big-IGF-II Isoforms Associated with Cancer

Science.gov (United States)

Greenall, Sameer A.; Bentley, John D.; Pearce, Lesley A.; Scoble, Judith A.; Sparrow, Lindsay G.; Bartone, Nicola A.; Xiao, Xiaowen; Baxter, Robert C.; Cosgrove, Leah J.; Adams, Timothy E.

2013-01-01

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed “pro” and “big” IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling. PMID:23166326

IGF-I, IGF-II, and Insulin Stimulate Different Gene Expression Responses through Binding to the IGF-I Receptor

DEFF Research Database (Denmark)

Versteyhe, Soetkin; Klaproth, Birgit; Borup, Rehannah

2013-01-01

Insulin and the insulin-like growth factors (IGF)-I and -II are closely related peptides important for regulation of metabolism, growth, differentiation, and development. The IGFs exert their main effects through the IGF-I receptor. Although the insulin receptor is the main physiological receptor...... for insulin, this peptide hormone can also bind at higher concentrations to the IGF-I receptor and exert effects through it. We used microarray gene expression profiling to investigate the gene expression regulated by IGF-I, IGF-II, and insulin after stimulation of the IGF-I receptor. Fibroblasts from mice......, knockout for IGF-II and the IGF-II/cation-independent mannose-6-phosphate receptor, and expressing functional IGF-I but no insulin receptors, were stimulated for 4 h with equipotent saturating concentrations of insulin, IGF-I, and IGF-II. Each ligand specifically regulated a group of transcripts...

Stability of XIST repression in relation to genomic imprinting following global genome demethylation in a human cell line

International Nuclear Information System (INIS)

Araújo, E.S.S. de; Vasques, L.R.; Stabellini, R.; Krepischi, A.C.V.; Pereira, L.V.

2014-01-01

DNA methylation is essential in X chromosome inactivation and genomic imprinting, maintaining repression of XIST in the active X chromosome and monoallelic repression of imprinted genes. Disruption of the DNA methyltransferase genes DNMT1 and DNMT3B in the HCT116 cell line (DKO cells) leads to global DNA hypomethylation and biallelic expression of the imprinted gene IGF2 but does not lead to reactivation of XIST expression, suggesting that XIST repression is due to a more stable epigenetic mark than imprinting. To test this hypothesis, we induced acute hypomethylation in HCT116 cells by 5-aza-2′-deoxycytidine (5-aza-CdR) treatment (HCT116-5-aza-CdR) and compared that to DKO cells, evaluating DNA methylation by microarray and monitoring the expression of XIST and imprinted genes IGF2, H19, and PEG10. Whereas imprinted genes showed biallelic expression in HCT116-5-aza-CdR and DKO cells, the XIST locus was hypomethylated and weakly expressed only under acute hypomethylation conditions, indicating the importance of XIST repression in the active X to cell survival. Given that DNMT3A is the only active DNMT in DKO cells, it may be responsible for ensuring the repression of XIST in those cells. Taken together, our data suggest that XIST repression is more tightly controlled than genomic imprinting and, at least in part, is due to DNMT3A

Stability of XIST repression in relation to genomic imprinting following global genome demethylation in a human cell line

Energy Technology Data Exchange (ETDEWEB)

Araújo, E.S.S. de [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Centro Internacional de Pesquisa, A.C. Camargo Cancer Center, São Paulo, SP (Brazil); Vasques, L.R. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Stabellini, R.; Krepischi, A.C.V. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Centro Internacional de Pesquisa, A.C. Camargo Cancer Center, São Paulo, SP (Brazil); Pereira, L.V. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil)

2014-10-17

DNA methylation is essential in X chromosome inactivation and genomic imprinting, maintaining repression of XIST in the active X chromosome and monoallelic repression of imprinted genes. Disruption of the DNA methyltransferase genes DNMT1 and DNMT3B in the HCT116 cell line (DKO cells) leads to global DNA hypomethylation and biallelic expression of the imprinted gene IGF2 but does not lead to reactivation of XIST expression, suggesting that XIST repression is due to a more stable epigenetic mark than imprinting. To test this hypothesis, we induced acute hypomethylation in HCT116 cells by 5-aza-2′-deoxycytidine (5-aza-CdR) treatment (HCT116-5-aza-CdR) and compared that to DKO cells, evaluating DNA methylation by microarray and monitoring the expression of XIST and imprinted genes IGF2, H19, and PEG10. Whereas imprinted genes showed biallelic expression in HCT116-5-aza-CdR and DKO cells, the XIST locus was hypomethylated and weakly expressed only under acute hypomethylation conditions, indicating the importance of XIST repression in the active X to cell survival. Given that DNMT3A is the only active DNMT in DKO cells, it may be responsible for ensuring the repression of XIST in those cells. Taken together, our data suggest that XIST repression is more tightly controlled than genomic imprinting and, at least in part, is due to DNMT3A.

Maternal nutrition during pregnancy is associated with differential expression of imprinted genes and DNA methyltranfereases in muscle of beef cattle offspring.

Science.gov (United States)

Wang, X; Lan, X; Radunz, A E; Khatib, H

2015-01-01

Maternal diet during pregnancy is a major determinant of the fetal developmental competence and may induce long-lasting epigenetic changes to the offspring. Imprinted genes have important roles in fetal programming, growth, and development. There are, however, limited data available on the influence of maternal diet on the expression of imprinted genes in beef cattle. Therefore, the objective of this study was to analyze the impact of maternal diet during pregnancy on the expression of 5 imprinted genes and 3 DNA methyltransferase genes in longissimus dorsi muscle from Angus calves. A total of 36 Angus-cross cows were inseminated to a single sire and on Day 135 of gestation they were randomly assigned to either low-starch (haylage) or high-starch (corn silage) diets. Diets were initially formulated to provide isocaloric and isonitrogenous intake. The H19, MEG8, IGF2R, and DNMT3a genes showed differential expression in longissimus dorsi muscle in calves between the diet groups. Given that high-starch diet is a source of energy for muscle growth and feed conversion efficiency in postnatal development, the mechanisms by which this diet affected expression of imprinted genes should be further explored.

Elevated expression of the IGF2 mRNA binding protein 2 (IGF2BP2/IMP2) is linked to short survival and metastasis in esophageal adenocarcinoma

OpenAIRE

Barghash, Ahmad; Golob-Schwarzl, Nicole; Helms, Volkhard; Haybaeck, Johannes; Kessler, Sonja M.

2016-01-01

Esophageal adenocarcinoma (EAC) represents the sixth leading cause of cancer-related deaths and develops in Barret's esophagus affected tissues. The IGF2 mRNA binding protein IMP2/IGF2BP2/p62 was originally identified as an autoantigen in hepatocellular carcinoma. Aim of this study was to investigate the expression and prognostic role of IMP2 in EAC. Human EAC and Barret's esophagus tissue showed overexpression of IMP2, particularly in tumors of increased size and in metastatic tissues. Molec...

IGF1 regulates RUNX1 expression via IRS1/2: Implications for antler chondrocyte differentiation

OpenAIRE

Yang, Zhan-Qing; Zhang, Hong-Liang; Duan, Cui-Cui; Geng, Shuang; Wang, Kai; Yu, Hai-Fan; Yue, Zhan-Peng; Guo, Bin

2017-01-01

Although IGF1 is important for the proliferation and differentiation of chondrocytes, its underlying molecular mechanism is still unknown. Here we addressed the physiologic function of IGF1 in antler cartilage and explored the interplay of IGF1, IRS1/2 and RUNX1 in chondrocyte differentiation. The results showed that IGF1 was highly expressed in antler chondrocytes. Exogenous rIGF1 could increase the proliferation of chondrocytes and cell proportion in the S phase, whereas IGF1R inhibitor PQ4...

The non-coding RNAs of the H19-IGF2 imprinted loci: a focus on biological roles and therapeutic potential in Lung Cancer.

Science.gov (United States)

Matouk, Imad J; Halle, David; Gilon, Michal; Hochberg, Abraham

2015-04-09

Since it was first described, the imprinted cluster 11p15.5 has been reported to be deregulated in a variety of pediatric and adult cancers including that of the lung. Both protein coding and non-coding genes functioning as oncogenes or as tumor suppressor genes reside within this cluster. Oncomirs that can function as oncogenes or as tumor suppressors have also been reported. While a complete account of the role played by the 11p15.5 imprinted cluster in lung cancer is beyond the scope of this review, we will focus on the role of the non-coding RNAs processed from the H19-IGF2 loci. A special emphasis will be given to the H19/miR-675 gene locus. Their potential diagnostic and therapeutic use in lung cancer will be described.

The dipeptide Pro-Asp promotes IGF-1 secretion and expression in hepatocytes by enhancing JAK2/STAT5 signaling pathway.

Science.gov (United States)

Wang, Songbo; Wang, Guoqing; Zhang, Mengyuan; Zhuang, Lu; Wan, Xiaojuan; Xu, Jingren; Wang, Lina; Zhu, Xiaotong; Gao, Ping; Xi, Qianyun; Zhang, Yongliang; Shu, Gang; Jiang, Qingyan

2016-11-15

It has been implicated that IGF-1 secretion can be regulated by dietary protein. However, whether the dipeptides, one of digested products of dietary protein, have influence on IGF-1 secretion remain largely unknown. Our study aimed to investigate the effects of the dipeptide Pro-Asp on IGF-1 secretion and expression in hepatocytes and to explore the possible underlying mechanisms. Our findings demonstrated that Pro-Asp promoted the secretion and gene expression of IGF-1 in HepG2 cells and primary porcine hepatocytes. Meanwhile, Pro-Asp activated the ERK and Akt signaling pathways, downstream of IGF-1. In addition, Pro-Asp enhanced GH-mediated JAK2/STAT5 signaling pathway, while inhibition of JAK2/STAT5 blocked the promotive effect of Pro-Asp on IGF-1 secretion and expression. Moreover, acute injection of Pro-Asp stimulated IGF-1 expression and activated JAK2/STAT5 signaling pathway in mice liver. Together, these results suggested that the dipeptide Pro-Asp promoted IGF-1 secretion and expression in hepatocytes by enhancing GH-mediated JAK2/STAT5 signaling pathway. Copyright © 2016. Published by Elsevier Ireland Ltd.

Let-7b Regulates Myoblast Proliferation by Inhibiting IGF2BP3 Expression in Dwarf and Normal Chicken

Science.gov (United States)

Lin, Shumao; Luo, Wen; Ye, Yaqiong; Bekele, Endashaw J.; Nie, Qinghua; Li, Yugu; Zhang, Xiquan

2017-01-01

The sex-linked dwarf chicken is caused by the mutation of growth hormone receptor (GHR) gene and characterized by shorter shanks, lower body weight, smaller muscle fiber diameter and fewer muscle fiber number. However, the precise regulatory pathways that lead to the inhibition of skeletal muscle growth in dwarf chickens still remain unclear. Here we found a let-7b mediated pathway might play important role in the regulation of dwarf chicken skeletal muscle growth. Let-7b has higher expression in the skeletal muscle of dwarf chicken than in normal chicken, and the expression of insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which is a translational activator of IGF2, showed opposite expression trend to let-7b. In vitro cellular assays validated that let-7b directly inhibits IGF2BP3 expression through binding to its 3′UTR region, and the protein level but not mRNA level of IGF2 would be reduced in let-7b overexpressed chicken myoblast. Let-7b can inhibit cell proliferation and induce cell cycle arrest in chicken myoblast through let-7b-IGF2BP3-IGF2 signaling pathway. Additionally, let-7b can also regulate skeletal muscle growth through let-7b-GHR-GHR downstream genes pathway, but this pathway is non-existent in dwarf chicken because of the deletion mutation of GHR 3′UTR. Notably, as the loss binding site of GHR for let-7b, let-7b has enhanced its binding and inhibition on IGF2BP3 in dwarf myoblast, suggesting that the miRNA can balance its inhibiting effect through dynamic regulate its binding to target genes. Collectively, these results not only indicate that let-7b can inhibit skeletal muscle growth through let-7b-IGF2BP3-IGF2 signaling pathway, but also show that let-7b regulates myoblast proliferation by inhibiting IGF2BP3 expression in dwarf and normal chickens. PMID:28736533

Prenatal famine and genetic variation are independently and additively associated with DNA methylation at regulatory loci within IGF2/H19.

Directory of Open Access Journals (Sweden)

Elmar W Tobi

Full Text Available Both the early environment and genetic variation may affect DNA methylation, which is one of the major molecular marks of the epigenome. The combined effect of these factors on a well-defined locus has not been studied to date. We evaluated the association of periconceptional exposure to the Dutch Famine of 1944-45, as an example of an early environmental exposure, and single nucleotide polymorphisms covering the genetic variation (tagging SNPs with DNA methylation at the imprinted IGF2/H19 region, a model for an epigenetically regulated genomic region. DNA methylation was measured at five differentially methylated regions (DMRs that regulate the imprinted status of the IGF2/H19 region. Small but consistent differences in DNA methylation were observed comparing 60 individuals with periconceptional famine exposure with unexposed same-sex siblings at all IGF2 DMRs (P(BH<0.05 after adjustment for multiple testing, but not at the H19 DMR. IGF2 DMR0 methylation was associated with IGF2 SNP rs2239681 (P(BH = 0.027 and INS promoter methylation with INS SNPs, including rs689, which tags the INS VNTR, suggesting a mechanism for the reported effect of the VNTR on INS expression (P(BH = 3.4 × 10(-3. Prenatal famine and genetic variation showed similar associations with IGF2/H19 methylation and their contributions were additive. They were small in absolute terms (<3%, but on average 0.5 standard deviations relative to the variation in the population. Our analyses suggest that environmental and genetic factors could have independent and additive similarly sized effects on DNA methylation at the same regulatory site.

IGF-I stimulates ERβ and aromatase expression via IGF1R/PI3K/AKT-mediated transcriptional activation in endometriosis.

Science.gov (United States)

Zhou, Yan; Zeng, Cheng; Li, Xin; Wu, Pei-Li; Yin, Ling; Yu, Xiao-Lan; Zhou, Ying-Fang; Xue, Qing

2016-08-01

Estrogen receptor beta (ERβ, encoded by ESR2 gene) and cytochrome P450 aromatase (encoded by CYP19A1 gene) play critical roles in endometriosis, and the levels of insulin-like growth factor-I (IGF-I) in the peritoneal fluid are significantly higher in patients with endometriosis compared with those in normal women. However, the effects and mechanisms of IGF-I on ERβ and aromatase expression remain to be fully elucidated. In this study, human endometriotic stromal cells (ESCs) and endometrial cells (EMs) derived from ovarian endometriomas and eutopic endometrial tissues. ESCs were cultured with IGF-I, signal pathway inhibitors, and siRNAs. ERβ and aromatase expression were measured by real-time PCR and Western, respectively. The binding of c-Jun and CREB to the ESR2 and CYP19A1 promoters was assessed by chromatin immunoprecipitation assay. Animal experiments were performed in a xenograft mouse model. Levels of IGF-I mRNA in ESCs were markedly higher than those in EMs. IGF-I upregulated ERβ and aromatase expression in ESCs after stimulation of the IGF1R/PI3K/AKT pathway. Following IGF-I treatment, a marked increase in c-Jun and CREB phosphorylation occurred, enhancing binding to the ESR2 and CYP19A1 promoters. An IGF1R inhibitor in vivo reduced IGF-I-induced endometriosis graft growth and ERβ and aromatase expression. In conclusion, this is the first report to describe a mechanistic analysis of ERβ and aromatase expression regulated by IGF-I in ESCs. Moreover, an IGF1R inhibitor impeded ectopic lesion growth in nude mice. These findings suggest that an inhibitor of IGF1R might have therapeutic potential as an antiendometriotic drug. Level of IGF-I mRNA in ESCs is markedly higher than that in EMs. IGF-I up-regulates ERβ and aromatase expression via IGF1R/PI3K/AKT pathway. C-Jun and CREB are recruited to ESR2 or CYP19A1 promoter by IGF-I stimulation. IGF-1R inhibitors in vivo impede the growth of ectopic lesions in nude mice.

Loss of insulin-like growth factor-II imprinting and the presence of screen-detected colorectal adenomas in women.

Science.gov (United States)

Woodson, Karen; Flood, Andrew; Green, Lisa; Tangrea, Joseph A; Hanson, Jeffrey; Cash, Brooks; Schatzkin, Arthur; Schoenfeld, Phillip

2004-03-03

Loss of imprinting (LOI) of insulin-like growth factor-II (IGF-II) may be an inherited epigenetic trait that is polymorphic in the population, and its presence may predispose an individual to the development of colorectal cancer. We evaluated the association between LOI of IGF-II in normal colonic mucosal samples and adenomas in women participating in a colonoscopy screening study. Among 40 participants, 11 (27.5%) had LOI of IGF-II in their normal colonic mucosal tissue. After adjusting for body mass index and family history of colorectal cancer, LOI status was associated with a fivefold increased risk of adenoma formation (odds ratio = 5.2, 95% confidence interval = 1.0 to 26.7). On average, IGF-II expression was more than threefold higher among women with LOI of IGF-II than among women with normal imprinting status. Our findings support the hypothesis that LOI of IGF-II is an epigenetic trait polymorphic in the population and suggest that LOI of IGF-II may play a role in colorectal cancer. These findings are intriguing and need to be confirmed in larger studies.

IGF-1R mRNA expression is increased in obese children.

Science.gov (United States)

Ricco, Rafaela Cristina; Ricco, Rubens Garcia; Queluz, Mariangela Carletti; de Paula, Mariana Teresa Sarti; Atique, Patricia Volpon; Custódio, Rodrigo José; Tourinho Filho, Hugo; Del Roio Liberatori, Raphael; Martinelli, Carlos Eduardo

2018-04-01

Obese children are often taller than age-matched subjects. Reports on GH and IGF-I levels in obese individuals are controversial, with normal and reduced GH-IGF-I levels having been reported in this group of patients. Thus, the aim of this study was to analyse insulin-like growth factor type 1 receptor (IGF-IR) mRNA expression in obese children. Forty-seven pre-pubertal children were included in this study: 29 were obese and taller than their target height, and 18 were normal eutrophic controls. Fasting blood samples were collected for IGF-IR mRNA expression in isolated lymphocytes and serum IGF-I, ALS, IGFBP-3, and IGFBP-1 concentration analysis. Relative IGF-IR gene expression (2 -ΔΔCT ) was significantly (P=0.025) higher in obese children (median 1.87) than in controls (1.15). Fourteen of the 29 obese subjects showed 2 -ΔΔCT values greater than or equal to 2, while only 2 individuals in the control group showed values above 2 (P=0.01). Obese children showed significantly (P=0.01) higher IGF-I concentrations than the control group (237ng/ml and 144ng/ml, respectively). Among obese patients, 65.5% had IGF-I values above the 75 percentile of the control group (P=0.02). ALS concentration was significantly (P=0.04) higher in the obese group, while IGFBP-3 levels were similar in obese and control children. IGFBP-1 concentration was lower in obese children, while insulin levels and HOMA-IR index were higher than in controls. The higher IGF-IR mRNA expression observed in obese children, associated with the higher IGF-I and ALS and the lower IGFBP-1 levels, suggest that the higher stature observed in these children may be due to increased IGF-I bioactivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Otx2 expression and implications for olfactory imprinting in the anemonefish, Amphiprion percula

Directory of Open Access Journals (Sweden)

Heather D. Veilleux

2013-07-01

The otx2 gene encodes a transcription factor (OTX2 essential in the formation of the brain and sensory systems. Specifically, OTX2-positive cells are associated with axons in the olfactory system of mice and otx2 is upregulated in odour-exposed zebrafish, indicating a possible role in olfactory imprinting. In this study, otx2 was used as a candidate gene to investigate the molecular mechanisms of olfactory imprinting to settlement cues in the coral reef anemonefish, Amphiprion percula. The A. percula otx2 (Ap-otx2 gene was elucidated, validated, and its expression tested in settlement-stage A. percula by exposing them to behaviourally relevant olfactory settlement cues in the first 24 hours post-hatching, or daily throughout the larval phase. In-situ hybridisation revealed expression of Ap-otx2 throughout the olfactory epithelium with increased transcript staining in odour-exposed settlement-stage larval fish compared to no-odour controls, in all scenarios. This suggests that Ap-otx2 may be involved in olfactory imprinting to behaviourally relevant settlement odours in A. percula.

Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

Science.gov (United States)

Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

2017-08-01

We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

Transcription factor ZBED6 mediates IGF2 gene expression by regulating promoter activity and DNA methylation in myoblasts

Science.gov (United States)

Zinc finger, BED-type containing 6 (ZBED6) is an important transcription factor in placental mammals, affecting development, cell proliferation and growth. In this study, we found that the expression of the ZBED6 and IGF2 were up regulated during C2C12 differentiation. The IGF2 expression levels wer...

Paternal Insulin-like Growth Factor 2 (Igf2 Regulates Stem Cell Activity During Adulthood

Directory of Open Access Journals (Sweden)

Vilma Barroca

2017-02-01

Full Text Available Insulin-like Growth Factor 2 (IGF2 belongs to the IGF/Insulin pathway, a highly conserved evolutionarily network that regulates growth, aging and lifespan. Igf2 is highly expressed in the embryo and in cancer cells. During mouse development, Igf2 is expressed in all sites where hematopoietic stem cells (HSC successively expand, then its expression drops at weaning and becomes undetectable when adult HSC have reached their niches in bones and start to self-renew. In the present study, we aim to discover the role of IGF2 during adulthood. We show that Igf2 is specifically expressed in adult HSC and we analyze HSC from adult mice deficient in Igf2 transcripts. We demonstrate that Igf2 deficiency avoids the age-related attrition of the HSC pool and that Igf2 is necessary for tissue homeostasis and regeneration. Our study reveals that the expression level of Igf2 is critical to maintain the balance between stem cell self-renewal and differentiation, presumably by regulating the interaction between HSC and their niche. Our data have major clinical interest for transplantation: understanding the changes in adult stem cells and their environments will improve the efficacy of regenerative medicine and impact health- and life-span.

Alteration in Expression and Methylation of IGF2/H19 in Placenta and Umbilical Cord Blood Are Associated with Macrosomia Exposed to Intrauterine Hyperglycemia.

Directory of Open Access Journals (Sweden)

Rina Su

Full Text Available Macrosomia is one of the most common complications in gestational diabetes mellitus. Insulin-like growth factor 2 and H19 are two of the imprinted candidate genes that are involved in fetal growth and development. Change in methylation at differentially methylated region of the insulin-like growth factor 2 and H19 has been proved to be an early event related to the programming of metabolic profile, including macrosomia and small for gestational age in offspring. Here we hypothesize that alteration in methylation at differentially methylated region of the insulin-like growth factor 2 and H19 is associated with macrosomia induced by intrauterine hyperglycemia.The expression of insulin-like growth factor 2 is significant higher in gestational diabetes mellitus group (GDM group compared to normal glucose tolerance group (NGT group both in umbilical cord blood and placenta, while the expression of H19 is significant lower in GDM group in umbilical cord blood. The expression of insulin-like growth factor 2 is significant higher in normal glucose tolerance with macrosomia group (NGT-M compared to normal glucose tolerance with normal birthweight group (NGT-NBW group both in placenta and umbilical cord blood. A model with interaction term of gene expression of IGF2 and H19 found that IGF2 and the joint action of IGF2 and H19 in placenta showed significantly relationship with GDM/NGT and GDM-NBW/NGT-NBW. A borderline significant association was seen among IGF2 and H19 in cord blood and GDM-M/NGT-M. The methylation level at different CpG sites of insulin-like growth factor 2 and H19 in umbilical cord blood was also significantly different among groups. Based on the multivariable linear regression analysis, the methylation of the insulin-like growth factor 2 / H19 is closely related to birth weight and intrauterine hyperglycemia.We confirmed the existence of alteration in DNA methylation in umbilical cord blood exposed to intrauterine hyperglycemia and

Matrix metalloproteinase-1 facilitates MSC migration via cleavage of IGF-2/IGFBP2 complex.

Science.gov (United States)

Guan, Shou P; Lam, Alan T L; Newman, Jennifer P; Chua, Kevin L M; Kok, Catherine Y L; Chong, Siao T; Chua, Melvin L K; Lam, Paula Y P

2018-01-01

The specific mechanism underlying the tumor tropism of human mesenchymal stem cells (MSCs) for cancer is not well defined. We previously showed that the migration potential of MSCs correlated with the expression and protease activity of matrix metalloproteinase (MMP)-1. Furthermore, highly tumor-tropic MSCs expressed higher levels of MMP-1 and insulin-like growth factor (IGF)-2 than poorly migrating MSCs. In this study, we examined the functional roles of IGF-2 and MMP-1 in mediating the tumor tropism of MSCs. Exogenous addition of either recombinant IGF-2 or MMP-1 could stimulate MSC migration. The correlation between IGF-2, MMP-1 expression, and MSC migration suggests that MMP-1 may play a role in regulating MSC migration via the IGF-2 signaling cascade. High concentrations of IGF binding proteins (IGFBPs) can inhibit IGF-stimulated functions by blocking its binding to its receptors and proteolysis of IGFBP is an important mechanism for the regulation of IGF signaling. We thus hypothesized that MMP-1 acts as an IGFBP2 proteinase, resulting in the cleavage of IGF-2/IGFBP2 complex and extracellular release of free IGF-2. Indeed, our results showed that conditioned media from highly migrating MSCs, which expressed high levels of MMP-1, cleaved the IGF-2/IGFBP2 complex. Taken together, these results showed that the MMP-1 secreted by highly tumor-tropic MSCs cleaved IGF-2/IGFBP2 complex. Free IGF-2 released from the complex may facilitate MSC migration toward tumor.

Differences in IGF-axis protein expression and survival among multiethnic breast cancer patients

International Nuclear Information System (INIS)

Hernandez, Brenda Y; Wilkens, Lynne R; Le Marchand, Loïc; Horio, David; Chong, Clayton D; Loo, Lenora W M

2015-01-01

There is limited knowledge about the biological basis of racial/ethnic disparities in breast cancer outcomes. Aberrations in IGF signaling induced by obesity and other factors may contribute to these disparities. This study examines the expression profiles of the insulin-like growth factor (IGF)-axis proteins and the association with breast cancer survival across a multiethnic population. We examined the expression profiles of the IGF1, IGF1R, IGFBP2 (IGF-binding proteins), and IGFBP3 proteins in breast tumor tissue and their relationships with all-cause and breast cancer-specific survival up to 17 years postdiagnosis in a multiethnic series of 358 patients in Hawaii, USA. Native Hawaiians, Caucasians, and Japanese were compared. Covariates included demographic and clinical factors and ER/PR/HER2 (estrogen receptor/progesterone receptor/human epidermal growth factor receptor-2) status. In Native Hawaiian patients, IGFBP2 and IGFBP3 expression were each independently associated with overall and breast cancer mortality (IGFB2: HR mort = 10.96, 95% CI: 2.18–55.19 and HR mort = 35.75, 95% CI: 3.64–350.95, respectively; IGFBP3: HR mort = 5.16, 95% CI: 1.27–20.94 and HR mort = 8.60, 95% CI: 1.84–40.15, respectively). IGF1R expression was also positively associated with all-cause mortality in Native Hawaiians. No association of IGF-axis protein expression and survival was observed in Japanese or Caucasian patients. The interaction of race/ethnicity and IGFBP3 expression on mortality risk was significant. IGF-axis proteins may have variable influence on breast cancer progression across different racial/ethnic groups. Expression of binding proteins and receptors in breast tumors may influence survival in breast cancer patients by inducing aberrations in IGF signaling and/or through IGF-independent mechanisms. Additional studies to evaluate the role of the IGF-axis in breast cancer are critical to improve targeted breast cancer treatment strategies

Potential roles for transposable elements in creating imprinted expression.

Science.gov (United States)

Anderson, Sarah N; Springer, Nathan M

2018-04-01

Changes in gene expression can have profound effects on phenotype. Nature has provided many complex patterns of gene regulation such as imprinting. Imprinted genes exhibit differences in the expression of the maternal and paternal alleles, even though they reside in the same nucleus with access to the same trans-acting factors. Significant attention has been focused on the potential reasons that imprinted expression could be beneficial and stabilized by selection. However, less attention has focused on understanding how imprinted expression might arise or decay. We discuss the evidence for frequent turnover of imprinted expression based on evolutionary analyses in plants and the potential role for transposable elements (TEs) in creating imprinted expression patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

Paternal Insulin-like Growth Factor 2 (Igf2) Regulates Stem Cell Activity During Adulthood.

Science.gov (United States)

Barroca, Vilma; Lewandowski, Daniel; Jaracz-Ros, Agnieszka; Hardouin, Sylvie-Nathalie

2017-02-01

Insulin-like Growth Factor 2 (IGF2) belongs to the IGF/Insulin pathway, a highly conserved evolutionarily network that regulates growth, aging and lifespan. Igf2 is highly expressed in the embryo and in cancer cells. During mouse development, Igf2 is expressed in all sites where hematopoietic stem cells (HSC) successively expand, then its expression drops at weaning and becomes undetectable when adult HSC have reached their niches in bones and start to self-renew. In the present study, we aim to discover the role of IGF2 during adulthood. We show that Igf2 is specifically expressed in adult HSC and we analyze HSC from adult mice deficient in Igf2 transcripts. We demonstrate that Igf2 deficiency avoids the age-related attrition of the HSC pool and that Igf2 is necessary for tissue homeostasis and regeneration. Our study reveals that the expression level of Igf2 is critical to maintain the balance between stem cell self-renewal and differentiation, presumably by regulating the interaction between HSC and their niche. Our data have major clinical interest for transplantation: understanding the changes in adult stem cells and their environments will improve the efficacy of regenerative medicine and impact health- and life-span. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Convergent and divergent evolution of genomic imprinting in the marsupial Monodelphis domestica

Directory of Open Access Journals (Sweden)

Das Radhika

2012-08-01

Full Text Available Abstract Background Genomic imprinting is an epigenetic phenomenon resulting in parent-of-origin specific monoallelic gene expression. It is postulated to have evolved in placental mammals to modulate intrauterine resource allocation to the offspring. In this study, we determined the imprint status of metatherian orthologues of eutherian imprinted genes. Results L3MBTL and HTR2A were shown to be imprinted in Monodelphis domestica (the gray short-tailed opossum. MEST expressed a monoallelic and a biallelic transcript, as in eutherians. In contrast, IMPACT, COPG2, and PLAGL1 were not imprinted in the opossum. Differentially methylated regions (DMRs involved in regulating imprinting in eutherians were not found at any of the new imprinted loci in the opossum. Interestingly, a novel DMR was identified in intron 11 of the imprinted IGF2R gene, but this was not conserved in eutherians. The promoter regions of the imprinted genes in the opossum were enriched for the activating histone modification H3 Lysine 4 dimethylation. Conclusions The phenomenon of genomic imprinting is conserved in Therians, but the marked difference in the number and location of imprinted genes and DMRs between metatherians and eutherians indicates that imprinting is not fully conserved between the two Therian infra-classes. The identification of a novel DMR at a non-conserved location as well as the first demonstration of histone modifications at imprinted loci in the opossum suggest that genomic imprinting may have evolved in a common ancestor of these two Therian infra-classes with subsequent divergence of regulatory mechanisms in the two lineages.

Epigenetic Consequences of Artificial Reproductive Technologies to the Bovine Imprinted Genes SNRPN, H19/IGF2 and IGF2R

Directory of Open Access Journals (Sweden)

Lawrence C. Smith

2015-02-01

Full Text Available Animal breeders have made widespread use of assisted reproductive technologies to accelerate genetic improvement programs aimed at obtaining more, better and cheaper food products. Selection approaches have traditionally focused on Mendel’s laws of inheritance using parental phenotypic characteristics and quantitative genetics approaches to choose the best parents for the next generation, regardless of their gender. However, apart from contributing DNA sequence variants, male and female gametes carry parental-specific epigenetic marks that play key roles during pre- and post-natal development and growth of the offspring. We herein review the epigenetic anomalies that are associated with artificial reproductive technologies in current use in animal breeding programs. For instance, we demonstrate that bovine embryos and foetuses derived by in vitro culture and somatic cell nuclear transfer show epigenetic anomalies in the differentially methylated regions controlling the expression of some imprinted genes. Although these genomic imprinting errors are undetected in the somatic tissues after birth, further research is warranted to examine potential germ cell transmission of epimutations and the potential risks of reproducing cattle using artificial reproductive technologies.

Investigation of PAX3/7-FKHR fusion genes and IGF2 gene expression in rhabdomyosarcoma tumors.

Science.gov (United States)

de Souza, Robson Ramos; Oliveira, Indhira Dias; Caran, Eliana Maria Monteiro; Alves, Maria Teresa de Seixas; Abib, Simone; Toledo, Silvia Regina Caminada

2012-12-01

The purpose of our study was to investigate the prevalence of the PAX3/7-FKHR fusion genes and quantify the IGF2 gene expression in rhabdomyosarcoma (RMS) samples. Soft tissue sarcomas account 5% of childhood cancers and 50% of them are RMS. Morphological evaluation of pediatric RMS has defined two histological subtypes, embryonal (ERMS) and alveolar (ARMS). Chromosomal analyses have demonstrated two translocations associated with ARMS, resulting in the PAX3/7-FKHR rearrangements. Reverse transcriptase-polymerase chain reaction (RT-PCR) is extremely useful in the diagnosis of ARMS positive for these rearrangements. Additionally, several studies have shown a significant involvement of IGF pathway in the pathogenesis of RMS. The presence of PAX3/7-FKHR gene fusions was studied in 25 RMS samples from patients attending the IOP-GRAACC/UNIFESP and three RMS cell lines by RT-PCR. IGF2 gene expression was quantified by qPCR and related with clinic pathological parameters. Of the 25 samples, nine (36%) were ARMS and 16 (64%) were ERMS. PAX3/7-FKHR gene fusions expression was detected in 56% of ARMS tumor samples. IGF2 overexpression was observed in 80% of samples and could indicate an important role of this pathway in RMS biology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort.

Science.gov (United States)

Soubry, Adelheid; Schildkraut, Joellen M; Murtha, Amy; Wang, Frances; Huang, Zhiqing; Bernal, Autumn; Kurtzberg, Joanne; Jirtle, Randy L; Murphy, Susan K; Hoyo, Cathrine

2013-02-06

Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene. We examined DNA from umbilical cord blood leukocytes from 79 newborns, born between July 2005 and November 2006 at Duke University Hospital, Durham, NC. Their mothers participated in the Newborn Epigenetics Study (NEST) during pregnancy. Parental characteristics were obtained via standardized questionnaires and medical records. DNA methylation patterns at two DMRs were analyzed by bisulfite pyrosequencing; one DMR upstream of IGF2 (IGF2 DMR), and one DMR upstream of the neighboring H19 gene (H19 DMR). Multiple regression models were used to determine potential associations between the offspring's DNA methylation patterns and parental obesity before conception. Obesity was defined as body mass index (BMI) ≥30 kg/m². Hypomethylation at the IGF2 DMR was associated with paternal obesity. Even after adjusting for several maternal and newborn characteristics, we observed a persistent inverse association between DNA methylation in the offspring and paternal obesity (β-coefficient was -5.28, P = 0.003). At the H19 DMR, no significant associations were detected between methylation patterns and paternal obesity. Our data suggest an increase in DNA methylation at the IGF2 and H19 DMRs among newborns from obese mothers, but a larger study

Does Metformin affect ER, PR, IGF-1R, β-catenin and PAX-2 expression in women with diabetes mellitus and endometrial cancer?

Science.gov (United States)

Markowska, Anna; Pawałowska, Monika; Filas, Violetta; Korski, Konstanty; Gryboś, Marian; Sajdak, Stefan; Olejek, Anita; Bednarek, Wiesława; Spiewankiewicz, Beata; Lubin, Jolanta; Markowska, Janina

2013-12-05

Diabetes mellitus, as a risk factor for endometrial cancer (EC), causes an increase in insulin and IGF-1 concentrations in the blood serum. The increase in insulin and IGF-1 are considered mitogenic factors contributory to cancer development. Studies suggest that metformin has preventive activity, decreasing mortality and the risk of neoplasms. Since estrogen (ER), progesterone (PR) and IGF-1 (IGF-1R) receptor expression and β-catenin and PAX-2 mutations are significant in the development of endometrial cancer, it was decided to study these factors in patients with endometrial cancer and type 2 diabetes mellitus (DM2), and to establish the effects of metformin on their expression. The expression of ER, PR, IGF-1R, β-catenin and PAX-2 have been immunohistochemically investigated in 86 type I endometrial cancer specimens. Patients were grouped according to the presence of DM2 and the type of hypoglycemic treatment administered. Comparing EC patients with DM2 and normal glycemic status, we found increased IGF-1R expression in women with DM2. A decrease in ER expression was noted in women with EC and DM2 receiving metformin as compared to women treated with insulin (p = 0.004). There was no statistically significant difference in PR, IGF-1R, β-catenin and PAX-2 expression among women receiving metformin and other hypoglycemic treatment. Although epidemiological studies suggest the beneficial role of metformin in many human cancers, there are still few studies confirming its favorable effect on endometrial cancer. Decreased ER expression in patients receiving metformin needs further research to allow evaluation of its clinical significance.

IGF-I and branchial IGF receptor expression and localization during salinity acclimation in striped bass

DEFF Research Database (Denmark)

Tipsmark, Christian Kølbaek; Luckenbach, John Adam; Madsen, Steffen

2007-01-01

The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass (Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small...... in either plasma IGF-I, liver, or gill IGF-I mRNA, or gill IGF-IR mRNA levels. In a separate experiment, FW-acclimated fish were injected with saline or IGF-I prior to a 24-h SW challenge. Rapid regain of osmotic balance following SW transfer was hindered by IGF-I. Immunohistochemistry revealed...

A downstream CpG island controls transcript initiation and elongation and the methylation state of the imprinted Airn macro ncRNA promoter.

Directory of Open Access Journals (Sweden)

Martha V Koerner

Full Text Available A CpG island (CGI lies at the 5' end of the Airn macro non-protein-coding (nc RNA that represses the flanking Igf2r promoter in cis on paternally inherited chromosomes. In addition to being modified on maternally inherited chromosomes by a DNA methylation imprint, the Airn CGI shows two unusual organization features: its position immediately downstream of the Airn promoter and transcription start site and a series of tandem direct repeats (TDRs occupying its second half. The physical separation of the Airn promoter from the CGI provides a model to investigate if the CGI plays distinct transcriptional and epigenetic roles. We used homologous recombination to generate embryonic stem cells carrying deletions at the endogenous locus of the entire CGI or just the TDRs. The deleted Airn alleles were analyzed by using an ES cell imprinting model that recapitulates the onset of Igf2r imprinted expression in embryonic development or by using knock-out mice. The results show that the CGI is required for efficient Airn initiation and to maintain the unmethylated state of the Airn promoter, which are both necessary for Igf2r repression on the paternal chromosome. The TDRs occupying the second half of the CGI play a minor role in Airn transcriptional elongation or processivity, but are essential for methylation on the maternal Airn promoter that is necessary for Igf2r to be expressed from this chromosome. Together the data indicate the existence of a class of regulatory CGIs in the mammalian genome that act downstream of the promoter and transcription start.

The IGF2-intron3-G3072A substitution explains a major imprinted QTL effect on backfat thickness in a Meishan x European white pig intercross

NARCIS (Netherlands)

Jungerius, B.J.; Laere, van A.S.; Pas, te M.F.W.; Oost, van B.A.; Andersson, L.; Groenen, M.A.M.

2004-01-01

A paternally expressed QTL for muscle growth and backfat thickness (BFT) has previously been identified near the IGF2 locus on the distal tip of pig chromosome 2 (SSC2p) in three experimental F-2 populations. Recently, a mutation in a regulatory element of the IGF2 gene was identified as the

The hepatic Igf2/H19 locus is not altered in 1-day old pups born to obese-prone Sprague-Dawley rats fed a low protein diet containing adequate folic acid

Science.gov (United States)

Gong et al. (Epigenetics, 2010) found, using diets low in folic acid, that compared to an 18% protein diet a 9% protein diet fed to pregnant Sprague-Dawley rats resulted in increased Igf2 and H19 gene expression in the liver of day 0 male offspring. In addition DNA methylation in the Imprinting Cont...

Regulation of insulin-like growth factor (IGF) I receptor expression during muscle cell differentiation. Potential autocrine role of IGF-II.

OpenAIRE

Rosenthal, S M; Brunetti, A; Brown, E J; Mamula, P W; Goldfine, I D

1991-01-01

Muscle is an important target tissue for insulin-like growth factor (IGF) action. The presence of specific, high affinity IGF receptors, as well as the expression of IGF peptides and binding proteins by muscle suggest that a significant component of IGF action in this tissue is mediated through autocrine and/or paracrine mechanisms. To explore autocrine/paracrine action of IGFs in muscle, we studied the regulation of the IGF-I receptor and the expression of IGF peptides during differentiation...

Comparisons of mRNA expression for insulin-like growth factor (IGF) type 2 receptor (IGF2R) and IGF-1 in small ovarian follicles between cattle selected and not selected for twin ovulations

Science.gov (United States)

Both IGF-1 and -2 stimulate ovarian follicular cell proliferation and antral follicle development. Actions of IGF-1 and -2 are mediated through the IGF type 1 receptor, whereas binding of IGF-2 to the IGF2R results in its degradation. Information on the role of IGF2R in regulating bovine follicula...

Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST cohort

Directory of Open Access Journals (Sweden)

Soubry Adelheid

2013-02-01

Full Text Available Abstract Background Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs of the imprinted Insulin-like Growth Factor 2 (IGF2 gene. Methods We examined DNA from umbilical cord blood leukocytes from 79 newborns, born between July 2005 and November 2006 at Duke University Hospital, Durham, NC. Their mothers participated in the Newborn Epigenetics Study (NEST during pregnancy. Parental characteristics were obtained via standardized questionnaires and medical records. DNA methylation patterns at two DMRs were analyzed by bisulfite pyrosequencing; one DMR upstream of IGF2 (IGF2 DMR, and one DMR upstream of the neighboring H19 gene (H19 DMR. Multiple regression models were used to determine potential associations between the offspring's DNA methylation patterns and parental obesity before conception. Obesity was defined as body mass index (BMI ≥30 kg/m2. Results Hypomethylation at the IGF2 DMR was associated with paternal obesity. Even after adjusting for several maternal and newborn characteristics, we observed a persistent inverse association between DNA methylation in the offspring and paternal obesity (β-coefficient was -5.28, P = 0.003. At the H19 DMR, no significant associations were detected between methylation patterns and paternal obesity. Our data suggest an increase in DNA methylation at the IGF2 and H19 DMRs among

Favorable prognostic value of SOCS2 and IGF-I in breast cancer

International Nuclear Information System (INIS)

Haffner, Michael C; Petridou, Barbara; Peyrat, Jean Phillipe; Révillion, Françoise; Müller-Holzner, Elisabeth; Daxenbichler, Günter; Marth, Christian; Doppler, Wolfgang

2007-01-01

Suppressor of cytokine signaling (SOCS) proteins comprise a protein family, which has initially been described as STAT induced inhibitors of the Jak/Stat pathway. Recent in vivo and in vitro studies suggest that SOCS proteins are also implicated in cancer. The STAT5 induced IGF-I acts as an endocrine and para/autocrine growth and differentiation factor in mammary gland development. Whereas high levels of circulating IGF-I have been associated with increased cancer risk, the role of autocrine acting IGF-I is less clear. The present study is aimed to elucidate the clinicopathological features associated with SOCS1, SOCS2, SOCS3, CIS and IGF-I expression in breast cancer. We determined the mRNA expression levels of SOCS1, SOCS2, SOCS3, CIS and IGF-I in 89 primary breast cancers by reverse transcriptase PCR. SOCS2 protein expression was further evaluated by immuno-blot and immunohistochemistry. SOCS2 expression inversely correlated with histopathological grade and ER positive tumors exhibited higher SOCS2 levels. Patients with high SOCS2 expression lived significantly longer (108.7 vs. 77.7 months; P = 0.015) and high SOCS2 expression proved to be an independent predictor for good prognosis (HR = 0.45, 95% CI 0.23 – 0.91, P = 0.026). In analogy to SOCS2, high IGF-I expression was an independent predictor for good prognosis in the entire patient cohort. In the subgroup of patients with lymph-node negative disease, high IGF-I was a strong predictor for favorable outcome in terms of overall survival and relapse free survival (HR = 0.075, 95% CI 0.014 – 0.388, P = 0.002). This is the first report on the favorable prognostic value of high SOCS2 expression in primary mammary carcinomas. Furthermore a strong association of high IGF-I expression levels with good prognosis was observed especially in lymph-node negative patients. Our results suggest that high expression of the STAT5 target genes SOCS2 and IGF-I is a feature of differentiated and less malignant tumors

Differential regulation of genomic imprinting by TET proteins in embryonic stem cells.

Science.gov (United States)

Liu, Lizhi; Mao, Shi-Qing; Ray, Chelsea; Zhang, Yu; Bell, Fong T; Ng, Sheau-Fang; Xu, Guo-Liang; Li, Xiajun

2015-09-01

TET proteins have been found to play an important role in active demethylation at CpG sites in mammals. There are some reports implicating their functions in removal of DNA methylation imprint at the imprinted regions in the germline. However, it is not well established whether TET proteins can also be involved in demethylation of DNA methylation imprint in embryonic stem (ES) cells. Here we report that loss of TET proteins caused a significant increase in DNA methylation at the Igf2-H19 imprinted region in ES cells. We also observed a variable increase in DNA methylation at the Peg1 imprinted region in the ES clones devoid of TET proteins, in particular in the differentiated ES cells. By contrast, we did not observe a significant increase of DNA methylation imprint at the Peg3, Snrpn and Dlk1-Dio3 imprinted regions in ES cells lacking TET proteins. Interestingly, loss of TET proteins did not result in a significant increase of DNA methylation imprint at the Igf2-H19 and Peg1 imprinted regions in the embryoid bodies (EB). Therefore, TET proteins seem to be differentially involved in maintaining DNA methylation imprint at a subset of imprinted regions in ES cells and EBs. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Imprinted Expression of SNRPN in Human Preimplantation Embryos

OpenAIRE

Huntriss, John; Daniels, Robert; Bolton, Virginia; Monk, Marilyn

1998-01-01

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two clinically distinct neurogenetic disorders arising from a loss of expression of imprinted genes within the human chromosome region 15q11-q13. Recent evidence suggests that the SNRPN gene, which is defective in PWS, plays a central role in the imprinting-center regulation of the PWS/AS region. To increase our understanding of the regulation of expression of this imprinted gene, we have developed single-cell-sensitive procedures for...

A fractionation method to identify qauntitative changes in protein expression mediated by IGF-1 on the proteome of murine C2C12 myoblasts

Directory of Open Access Journals (Sweden)

Friedmann Theodore

2009-08-01

Full Text Available Abstract Although much is known about signal transduction downstream of insulin-like growth factor-1 (IGF-1, relatively little is known about the global changes in protein expression induced by this hormone. In this study, the acute effects of IGF-1 on the proteome of murine C2C12 cells were examined. Cells were treated with IGF-1 for up to 24 hours, lysed, and fractionated into cytosolic, nuclear, and insoluble portions. Proteins from the cytosolic fraction were further separated using a new batch ion-exchange chromatography method to reduce sample complexity, followed by two-dimensional (2D electrophoresis, and identification of selected proteins by mass spectrometry. PDQuest software was utilized to identify and catalogue temporal changes in protein expression during IGF-1 stimulation. In response to IGF-1 stimulation, expression of 23 proteins increased at least three-fold and expression of 17 proteins decreased at least three-fold compared with control un-stimulated C2C12 cells. Changes in expression of selected proteins from each group, including Rho-GDI, cofillin, RAD50, enolase, IκB kinase b (IκBKb and Hsp70 were confirmed by Western blotting. Additionally, the position of 136 'landmark' proteins whose expression levels and physicochemical properties did not change appreciably or consistently during IGF-1 treatment were mapped and identified. This characterization of large-scale changes in protein expression in response to growth factor stimulation of C2C12 cells will further help to establish a comprehensive understanding of the networks and pathways involved in the action of IGF-1.

BRCA1 is expressed in uterine serous carcinoma (USC) and controls insulin-like growth factor I receptor (IGF-IR) gene expression in USC cell lines.

Science.gov (United States)

Amichay, Keren; Kidron, Debora; Attias-Geva, Zohar; Schayek, Hagit; Sarfstein, Rive; Fishman, Ami; Werner, Haim; Bruchim, Ilan

2012-06-01

The insulin-like growth factor I receptor (IGF-IR) and BRCA1 affect cell growth and apoptosis. Little information is available about BRCA1 activity on the IGF signaling pathway. This study evaluated the effect of BRCA1 on IGF-IR expression. BRCA1 and IGF-IR immunohistochemistry on archival tissues (35 uterine serous carcinomas [USCs] and 17 metastases) were performed. USPC1 and USPC2 cell lines were transiently cotransfected with an IGF-IR promoter construct driving a luciferase reporter gene and a BRCA1 expression plasmid. Endogenous IGF-IR levels were evaluated by Western immunoblotting. We found high BRCA1 and IGF-IR protein expression in primary and metastatic USC tumors. All samples were immunostained for BRCA1-71% strongly stained; and 33/35 (94%) were stained positive for IGF-IR-2 (6%) strongly stained. No difference in BRCA1 and IGF-IR staining intensity was noted between BRCA1/2 mutation carriers and noncarriers. Metastatic tumors stained more intensely for BRCA1 than did the primary tumor site (P = 0.041) and with borderline significance for IGF-IR (P = 0.069). BRCA1 and IGF-IR staining did not correlate to survival. BRCA1 expression led to 35% and 54% reduction in IGF-IR promoter activity in the USPC1 and USCP2 cell lines, respectively. Western immunoblotting showed a decline in phosphorylated IGF-IR and phosphorylated AKT in both transiently and stably transfected cells. BRCA1 and IGF-IR are highly expressed in USC tumors. BRCA1 suppresses IGF-IR gene expression and activity. These findings suggest a possible biological link between the BRCA1 and the IGF-I signaling pathways in USC. The clinical implications of this association need to be explored.

Favorable prognostic value of SOCS2 and IGF-I in breast cancer

Directory of Open Access Journals (Sweden)

Daxenbichler Günter

2007-07-01

Full Text Available Abstract Background Suppressor of cytokine signaling (SOCS proteins comprise a protein family, which has initially been described as STAT induced inhibitors of the Jak/Stat pathway. Recent in vivo and in vitro studies suggest that SOCS proteins are also implicated in cancer. The STAT5 induced IGF-I acts as an endocrine and para/autocrine growth and differentiation factor in mammary gland development. Whereas high levels of circulating IGF-I have been associated with increased cancer risk, the role of autocrine acting IGF-I is less clear. The present study is aimed to elucidate the clinicopathological features associated with SOCS1, SOCS2, SOCS3, CIS and IGF-I expression in breast cancer. Methods We determined the mRNA expression levels of SOCS1, SOCS2, SOCS3, CIS and IGF-I in 89 primary breast cancers by reverse transcriptase PCR. SOCS2 protein expression was further evaluated by immuno-blot and immunohistochemistry. Results SOCS2 expression inversely correlated with histopathological grade and ER positive tumors exhibited higher SOCS2 levels. Patients with high SOCS2 expression lived significantly longer (108.7 vs. 77.7 months; P = 0.015 and high SOCS2 expression proved to be an independent predictor for good prognosis (HR = 0.45, 95% CI 0.23 – 0.91, P = 0.026. In analogy to SOCS2, high IGF-I expression was an independent predictor for good prognosis in the entire patient cohort. In the subgroup of patients with lymph-node negative disease, high IGF-I was a strong predictor for favorable outcome in terms of overall survival and relapse free survival (HR = 0.075, 95% CI 0.014 – 0.388, P = 0.002. Conclusion This is the first report on the favorable prognostic value of high SOCS2 expression in primary mammary carcinomas. Furthermore a strong association of high IGF-I expression levels with good prognosis was observed especially in lymph-node negative patients. Our results suggest that high expression of the STAT5 target genes SOCS2 and IGF

IGF-1 attenuates LPS induced pro-inflammatory cytokines expression in buffalo (Bubalus bubalis) granulosa cells.

Science.gov (United States)

Onnureddy, K; Ravinder; Onteru, Suneel Kumar; Singh, Dheer

2015-03-01

Interaction between immune and endocrine system is a diverse process influencing cellular function and homeostasis in animals. Negative energy balance (NEB) during postpartum period in dairy animals usually suppresses these systems resulting in reproductive tract infection and infertility. These negative effects could be due to competition among endocrine and immune signaling pathways for common signaling molecules. The present work studied the effect of IGF-1 (50 ng/ml) on LPS (1 μg/ml) mediated pro-inflammatory cytokine expression (IL-1β, TNF-α, IL-6) and aromatase (CYP19A1) genes' expressions as well as proliferation of buffalo granulosa cells. The crosstalk between LPS and IGF-1 was also demonstrated through studying the activities of downstream signaling molecules (ERK1/2, Akt, NF-κB) by western blot and immunostaining. Gene expression analysis showed that IGF-1 significantly reduced the LPS induced expression of IL-1β, TNF-α and IL-6. LPS alone inhibited the CYP19A1 expression. However, co-treatment with IGF-1 reversed the inhibitory effect of LPS on CYP19A1 expression. LPS alone did not affect granulosa cell proliferation, but co-treatment with IGF-1, and IGF-1 alone enhanced the proliferation. Western blot results demonstrated that LPS caused the nuclear translocation of the NF-κB and increased the phosphorylation of ERK1/2 and Akt maximum at 15 min and 60 min, respectively. Nonetheless, co-treatment with IGF-1 delayed LPS induced phosphorylation of ERK1/2 (peak at 120 min), while promoting early Akt phosphorylation (peak at 5 min) with no effect on NF-κB translocation. Overall, IGF-1 delayed and reversed the effects of LPS, suggesting that high IGF-1 levels may combat infection during critical periods like NEB in postpartum dairy animals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Relationship between serum IGF-1 and skeletal muscle IGF-1 mRNA expression to phosphocreatine recovery after exercise in obese men with reduced GH.

Science.gov (United States)

Hamarneh, Sulaiman R; Murphy, Caitlin A; Shih, Cynthia W; Frontera, Walter; Torriani, Martin; Irazoqui, Javier E; Makimura, Hideo

2015-02-01

GH and IGF-1 are believed to be physiological regulators of skeletal muscle mitochondria. The objective of this study was to examine the relationship between GH/IGF-1 and skeletal muscle mitochondria in obese subjects with reduced GH secretion in more detail. Fifteen abdominally obese men with reduced GH secretion were treated for 12 weeks with recombinant human GH. Subjects underwent (31)P-magnetic resonance spectroscopy to assess phosphocreatine (PCr) recovery as an in vivo measure of skeletal muscle mitochondrial function and percutaneous muscle biopsies to assess mRNA expression of IGF-1 and mitochondrial-related genes at baseline and 12 weeks. At baseline, skeletal muscle IGF-1 mRNA expression was significantly associated with PCr recovery (r = 0.79; P = .01) and nuclear respiratory factor-1 (r = 0.87; P = .001), mitochondrial transcription factor A (r = 0.86; P = .001), peroxisome proliferator-activated receptor (PPAR)γ (r = 0.72; P = .02), and PPARα (r = 0.75; P = .01) mRNA expression, and trended to an association with PPARγ coactivator 1-α (r = 0.59; P = .07) mRNA expression. However, serum IGF-1 concentration was not associated with PCr recovery or any mitochondrial gene expression (all P > .10). Administration of recombinant human GH increased both serum IGF-1 (change, 218 ± 29 μg/L; P IGF-1 mRNA in muscle (fold change, 2.1 ± 0.3; P = .002). Increases in serum IGF-1 were associated with improvements in total body fat (r = -0.53; P = .04), trunk fat (r = -0.55; P = .03), and lean mass (r = 0.58; P = .02), but not with PCr recovery (P > .10). Conversely, increase in muscle IGF-1 mRNA was associated with improvements in PCr recovery (r = 0.74; P = .02), but not with body composition parameters (P > .10). These data demonstrate a novel association of skeletal muscle mitochondria with muscle IGF-1 mRNA expression, but independent of serum IGF-1 concentrations.

Identification and resolution of artifacts in the interpretation of imprinted gene expression.

Science.gov (United States)

Proudhon, Charlotte; Bourc'his, Déborah

2010-12-01

Genomic imprinting refers to genes that are epigenetically programmed in the germline to express exclusively or preferentially one allele in a parent-of-origin manner. Expression-based genome-wide screening for the identification of imprinted genes has failed to uncover a significant number of new imprinted genes, probably because of the high tissue- and developmental-stage specificity of imprinted gene expression. A very large number of technical and biological artifacts can also lead to the erroneous evidence of imprinted gene expression. In this article, we focus on three common sources of potential confounding effects: (i) random monoallelic expression in monoclonal cell populations, (ii) genetically determined monoallelic expression and (iii) contamination or infiltration of embryonic tissues with maternal material. This last situation specifically applies to genes that occur as maternally expressed in the placenta. Beside the use of reciprocal crosses that are instrumental to confirm the parental specificity of expression, we provide additional methods for the detection and elimination of these situations that can be misinterpreted as cases of imprinted expression.

Maternal low protein diet and postnatal high fat diet increases adipose imprinted gene expression

Science.gov (United States)

Maternal and postnatal diet can alter Igf2 gene expression and DNA methylation. To test whether maternal low protein and postnatal high fat (HF) diet result in alteration in Igf2 expression and obesity, we fed obese-prone Sprague-Dawley rats 8% (LP) or 20% (NP) protein for 3 wk prior to breeding and...

Chromosome 15 structural abnormalities: effect on IGF1R gene expression and function

Directory of Open Access Journals (Sweden)

Rossella Cannarella

2017-09-01

Full Text Available Insulin-like growth factor 1 receptor (IGF1R, mapping on the 15q26.3 chromosome, is required for normal embryonic and postnatal growth. The aim of the present study was to evaluate the IGF1R gene expression and function in three unrelated patients with chromosome 15 structural abnormalities. We report two male patients with the smallest 15q26.3 chromosome duplication described so far, and a female patient with ring chromosome 15 syndrome. Patient one, with a 568 kb pure duplication, had overgrowth, developmental delay, mental and psychomotor retardation, obesity, cryptorchidism, borderline low testis volume, severe oligoasthenoteratozoospermia and gynecomastia. We found a 1.8-fold increase in the IGF1R mRNA and a 1.3-fold increase in the IGF1R protein expression (P < 0.05. Patient two, with a 650 kb impure duplication, showed overgrowth, developmental delay, mild mental retardation, precocious puberty, low testicular volume and severe oligoasthenoteratozoospermia. The IGF1R mRNA and protein expression was similar to that of the control. Patient three, with a 46,XX r(15 (p10q26.2 karyotype, displayed intrauterine growth retardation, developmental delay, mental and psychomotor retardation. We found a <0.5-fold decrease in the IGF1R mRNA expression and an undetectable IGF1R activity. After reviewing the previously 96 published cases of chromosome 15q duplication, we found that neurological disorders, congenital cardiac defects, typical facial traits and gonadal abnormalities are the prominent features in patients with chromosome 15q duplication. Interestingly, patients with 15q deletion syndrome display similar features. We speculate that both the increased and decreased IGF1R gene expression may play a role in the etiology of neurological and gonadal disorders.

DDC and COBL, flanking the imprinted GRB10 gene on 7p12, are biallelically expressed.

Science.gov (United States)

Hitchins, Megan P; Bentley, Louise; Monk, David; Beechey, Colin; Peters, Jo; Kelsey, Gavin; Ishino, Fumitoshi; Preece, Michael A; Stanier, Philip; Moore, Gudrun E

2002-12-01

Maternal duplication of human 7p11.2-p13 has been associated with Silver-Russell syndrome (SRS) in two familial cases. GRB10 is the only imprinted gene identified within this region to date. GRB10 demonstrates an intricate tissue- and isoform-specific imprinting profile in humans, with paternal expression in fetal brain and maternal expression of one isoform in skeletal muscle. The mouse homolog is maternally transcribed. The GRB10 protein is a potent growth inhibitor and represents a candidate for SRS, which is characterized by pre- and postnatal growth retardation and a spectrum of additional dysmorphic features. Since imprinted genes tend to be grouped in clusters, we investigated the imprinting status of the dopa-decarboxylase gene (DDC) and the Cordon-bleu gene (COBL) which flank GRB10 within the 7p11.2-p13 SRS duplicated region. Although both genes were found to replicate asynchronously, suggestive of imprinting, SNP expression analyses showed that neither gene was imprinted in multiple human fetal tissues. The mouse homologues, Ddc and Cobl, which map to the homologous imprinted region on proximal Chr 11, were also biallelically expressed in mice with uniparental maternal or paternal inheritance of this region. With the intent of using mouse Grb10 as an imprinted control, biallelic expression was consistently observed in fetal, postnatal, and adult brain of these mice, in contrast to the maternal-specific transcription previously demonstrated in brain in inter-specific F1 progeny. This may be a further example of over-expression of maternally derived transcripts in inter-specific mouse crosses. GRB10 remains the only imprinted gene identified within 7p11.2-p13.

Analysis artefacts of the INS-IGF2 fusion transcript

DEFF Research Database (Denmark)

Wernersson, Rasmus; Frogne, Thomas; Rescan, Claude

2015-01-01

Background: In gene expression analysis, overlapping genes, splice variants, and fusion transcripts are potential sources of data analysis artefacts, depending on how the observed intensity is assigned to one, or more genes. We here exemplify this by an in-depth analysis of the INS-IGF2 fusion...... transcript, which has recently been reported to be among the highest expressed transcripts in human pancreatic beta cells and its protein indicated as a novel autoantigen in Type 1 Diabetes. Results: Through RNA sequencing and variant specific qPCR analyses we demonstrate that the true abundance of INS-IGF2...... is >20,000 fold lower than INS in human beta cells, and we suggest an explanation to the nature of the artefacts which have previously led to overestimation of the gene expression level in selected studies. We reinvestigated the previous reported findings of detection of INS-IGF2 using antibodies both...

High-throughput analysis of candidate imprinted genes and allele-specific gene expression in the human term placenta

Directory of Open Access Journals (Sweden)

Clark Taane G

2010-04-01

Full Text Available Abstract Background Imprinted genes show expression from one parental allele only and are important for development and behaviour. This extreme mode of allelic imbalance has been described for approximately 56 human genes. Imprinting status is often disrupted in cancer and dysmorphic syndromes. More subtle variation of gene expression, that is not parent-of-origin specific, termed 'allele-specific gene expression' (ASE is more common and may give rise to milder phenotypic differences. Using two allele-specific high-throughput technologies alongside bioinformatics predictions, normal term human placenta was screened to find new imprinted genes and to ascertain the extent of ASE in this tissue. Results Twenty-three family trios of placental cDNA, placental genomic DNA (gDNA and gDNA from both parents were tested for 130 candidate genes with the Sequenom MassArray system. Six genes were found differentially expressed but none imprinted. The Illumina ASE BeadArray platform was then used to test 1536 SNPs in 932 genes. The array was enriched for the human orthologues of 124 mouse candidate genes from bioinformatics predictions and 10 human candidate imprinted genes from EST database mining. After quality control pruning, a total of 261 informative SNPs (214 genes remained for analysis. Imprinting with maternal expression was demonstrated for the lymphocyte imprinted gene ZNF331 in human placenta. Two potential differentially methylated regions (DMRs were found in the vicinity of ZNF331. None of the bioinformatically predicted candidates tested showed imprinting except for a skewed allelic expression in a parent-specific manner observed for PHACTR2, a neighbour of the imprinted PLAGL1 gene. ASE was detected for two or more individuals in 39 candidate genes (18%. Conclusions Both Sequenom and Illumina assays were sensitive enough to study imprinting and strong allelic bias. Previous bioinformatics approaches were not predictive of new imprinted genes

Quantification of expression and methylation of the Igf2r imprinted gene in segmental trisomic mouse model

Czech Academy of Sciences Publication Activity Database

Vacík, Tomáš; Forejt, Jiří

2003-01-01

Roč. 82, - (2003), s. 261-268 ISSN 0888-7543 R&D Projects: GA MŠk LN00A079; GA ČR GV204/98/K015 Grant - others:HHMI(US) 555000306 Institutional research plan: CEZ:AV0Z5052915 Keywords : Genomic imprinting * dosage-sensitive genes * Ts43H segmental trisomy of chromosome 17 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.488, year: 2003

Insulin-like growth factor 2 (IGF2) modulates murine hematopoietic stem cell maintenance through upregulation of p57

Science.gov (United States)

Thomas, Dolly D.; Sommer, Andreia Gianotti; Balazs, Alejandro B.; Beerman, Isabel; Murphy, George J.; Rossi, Derrick; Mostoslavsky, Gustavo

2017-01-01

Hematopoietic stem cells (HSC) rely on a highly regulated molecular network to balance self-renewal and lineage specification to sustain life-long hematopoiesis. Despite a plethora of studies aimed at identifying molecules governing HSC fate, our current knowledge of the genes responsible is limited. We have found Insulin-like growth factor 2 (IGF2) to be predominantly expressed within long-term HSC. This study examines IGF2 expression patterns and the effects of the gene in HSC. Through the overexpression and knockdown of IGF2 within purified HSC, we demonstrate that IGF2 expression increases HSC-derived multilineage colonies in vitro and enhances hematopoietic contribution in vivo upon competitive bone marrow transplantation. The effects of IGF2 are mediated by direct upregulation of the CDKi p57, exclusively within long-term HSC, via activation of the PI3K-Akt pathway. Increased expression of p57 resulted in a concomitant increase of HSC in the G0/G1 stage of the cell cycle. Analysis of genomic DNA methylation revealed that HSC exhibited a hypomethylated state within the promoter region of the CDKN1C (p57) gene, providing a potential mechanism for the exclusive effects of IGF2 within HSC. Our studies demonstrate a novel role for IGF2 in regulating HSC cell cycle and illustrate potential novel therapeutic targets for hematological diseases. PMID:26872540

IGF-1 modulates gene expression of proteins involved in inflammation, cytoskeleton, and liver architecture.

Science.gov (United States)

Lara-Diaz, V J; Castilla-Cortazar, I; Martín-Estal, I; García-Magariño, M; Aguirre, G A; Puche, J E; de la Garza, R G; Morales, L A; Muñoz, U

2017-05-01

Even though the liver synthesizes most of circulating IGF-1, it lacks its receptor under physiological conditions. However, according to previous studies, a damaged liver expresses the receptor. For this reason, herein, we examine hepatic histology and expression of genes encoding proteins of the cytoskeleton, extracellular matrix, and cell-cell molecules and inflammation-related proteins. A partial IGF-1 deficiency murine model was used to investigate IGF-1's effects on liver by comparing wild-type controls, heterozygous igf1 +/- , and heterozygous mice treated with IGF-1 for 10 days. Histology, microarray for mRNA gene expression, RT-qPCR, and lipid peroxidation were assessed. Microarray analyses revealed significant underexpression of igf1 in heterozygous mice compared to control mice, restoring normal liver expression after treatment, which then normalized its circulating levels. IGF-1 receptor mRNA was overexpressed in Hz mice liver, while treated mice displayed a similar expression to that of the controls. Heterozygous mice showed overexpression of several genes encoding proteins related to inflammatory and acute-phase proteins and underexpression or overexpression of genes which coded for extracellular matrix, cytoskeleton, and cell junction components. Histology revealed an altered hepatic architecture. In addition, liver oxidative damage was found increased in the heterozygous group. The mere IGF-1 partial deficiency is associated with relevant alterations of the hepatic architecture and expression of genes involved in cytoskeleton, hepatocyte polarity, cell junctions, and extracellular matrix proteins. Moreover, it induces hepatic expression of the IGF-1 receptor and elevated acute-phase and inflammation mediators, which all resulted in liver oxidative damage.

Pancreatic Fibroblasts Stimulate the Motility of Pancreatic Cancer Cells through IGF1/IGF1R Signaling under Hypoxia.

Directory of Open Access Journals (Sweden)

Toshiki Hirakawa

Full Text Available Pancreatic ductal adenocarcinoma (PDAC is characterized by its hypovascularity, with an extremely poor prognosis because of its highly invasive nature. PDAC proliferates with abundant stromal cells, suggesting that its invasive activity might be controlled by intercellular interactions between cancer cells and fibroblasts. Using four PDAC cell lines and two pancreas cancer-associated fibroblasts (CAFs, the expression of insulin-like growth factor-1 (IGF1 and IGF1 receptor (IGF1R was evaluated by RT-PCR, FACScan, western blot, or ELISA. Correlation between IGF1R and the hypoxia marker carbonic anhydrase 9 (CA9 was examined by immunohistochemical staining of 120 pancreatic specimens. The effects of CAFs, IGF1, and IGF1R inhibitors on the motility of cancer cells were examined by wound-healing assay or invasion assay under normoxia (20% O2 and hypoxia (1% O2. IGF1R expression was significantly higher in RWP-1, MiaPaCa-2, and OCUP-AT cells than in Panc-1 cells. Hypoxia increased the expression level of IGF1R in RWP-1, MiaPaCa-2, and OCUP-AT cells. CA9 expression was correlated with IGF1R expression in pancreatic specimens. CAFs produced IGF1 under hypoxia, but PDAC cells did not. A conditioned medium from CAFs, which expressed αSMA, stimulated the migration and invasion ability of MiaPaCa-2, RWP-1, and OCUP-AT cells. The motility of all PDAC cells was greater under hypoxia than under normoxia. The motility-stimulating ability of CAFs was decreased by IGF1R inhibitors. These findings might suggest that pancreas CAFs stimulate the invasion activity of PDAC cells through paracrine IGF1/IGF1R signaling, especially under hypoxia. Therefore the targeting of IGF1R signaling might represent a promising therapeutic approach in IGF1R-dependent PDAC.

Insulin-like growth factor 1 (IGF1) and its active peptide (1-3)IGF1 enhance the expression of synaptic markers in neuronal circuits through different cellular mechanisms.

LENUS (Irish Health Repository)

Corvin, Aiden P

2012-06-27

Insulin-like growth factor-1 (IGF1) and its active peptide (1-3)IGF1 modulate brain growth and plasticity and are candidate molecules for treatment of brain disorders. IGF1 N-terminal portion is naturally cleaved to generate the tri-peptide (1-3)IGF1 (glycine-praline-glutamate). IGF1 and (1-3)IGF have been proposed as treatment for neuropathologies, yet their effect on nerve cells has not been directly compared. In this study we examine the effects of IGF1 and (1-3)IGF1 in primary cortical cultures and measure the expression levels of markers for intracellular pathways and synaptic function. We find that both treatments activate the IGF1 receptor and enhance the expression of synaptic markers, however, they activate different intracellular pathways. Furthermore, (1-3)IGF1 administration increases the expression of endogenous IGF1, suggesting a direct interaction between the two molecules. The results show that the two molecules increase the expression of synaptic proteins through activating different cellular mechanisms.

Sodium arsenite represses the expression of myogenin in C2C12 mouse myoblast cells through histone modifications and altered expression of Ezh2, Glp, and Igf-1

Energy Technology Data Exchange (ETDEWEB)

Hong, Gia-Ming [Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Present address: The University of Chicago, Section of Hematology/Oncology, 900 E. 57th Street, Room 7134, Chicago, IL 60637 (United States); Bain, Lisa J., E-mail: lbain@clemson.edu [Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States)

2012-05-01

Arsenic is a toxicant commonly found in water systems and chronic exposure can result in adverse developmental effects including increased neonatal death, stillbirths, and miscarriages, low birth weight, and altered locomotor activity. Previous studies indicate that 20 nM sodium arsenite exposure to C2C12 mouse myocyte cells delayed myoblast differentiation due to reduced myogenin expression, the transcription factor that differentiates myoblasts into myotubes. In this study, several mechanisms by which arsenic could alter myogenin expression were examined. Exposing differentiating C2C12 cells to 20 nM arsenic increased H3K9 dimethylation (H3K9me2) and H3K9 trimethylation (H3K9me3) by 3-fold near the transcription start site of myogenin, which is indicative of increased repressive marks, and reduced H3K9 acetylation (H3K9Ac) by 0.5-fold, indicative of reduced permissive marks. Protein expression of Glp or Ehmt1, a H3-K9 methyltransferase, was also increased by 1.6-fold in arsenic-exposed cells. In addition to the altered histone remodeling status on the myogenin promoter, protein and mRNA levels of Igf-1, a myogenic growth factor, were significantly repressed by arsenic exposure. Moreover, a 2-fold induction of Ezh2 expression, and an increased recruitment of Ezh2 (3.3-fold) and Dnmt3a (∼ 2-fold) to the myogenin promoter at the transcription start site (− 40 to + 42), were detected in the arsenic-treated cells. Together, we conclude that the repressed myogenin expression in arsenic-exposed C2C12 cells was likely due to a combination of reduced expression of Igf-1, enhanced nuclear expression and promoter recruitment of Ezh2, and altered histone remodeling status on myogenin promoter (− 40 to + 42). -- Highlights: ► Igf-1 expression is decreased in C2C12 cells after 20 nM arsenite exposure. ► Arsenic exposure alters histone remodeling on the myogenin promoter. ► Glp expression, a H3–K9 methyltransferase, was increased in arsenic-exposed cells. ► Ezh2

Gene Expression of IGF1, IGF1R, and IGFBP3 in Epiretinal Membranes of Patients with Proliferative Diabetic Retinopathy: Preliminary Study

Directory of Open Access Journals (Sweden)

Dorota Romaniuk

2013-01-01

Full Text Available The molecular mechanism formation of secondary epiretinal membranes (ERMs after proliferative diabetic retinopathy (PDR or primary idiopathic ERMs is still poorly understood. Therefore, the present study focused on the assessment of IGF1, IGF1R, and IGFBP3 mRNA levels in ERMs and PBMCs from patients with PDR. The examined group comprised 6 patients with secondary ERMs after PDR and the control group consisted of 11 patients with idiopathic ERMs. Quantification of IGF1, IGF1R, and IGFBP3 mRNAs was performed by real-time QRT-PCR technique. In ERMs, IGF1 and IGF1R mRNA levels were significantly higher in patients with diabetes compared to control subjects. In PBMCs, there were no statistically significant differences of IGF1, IGF1R, and IGFBP3 expression between diabetic and nondiabetic patients. In conclusion, our study indicated IGF1 and IGF1R differential expression in ERMs, but not in PBMCs, of diabetic and nondiabetic patients, suggesting that these factors can be involved in the pathogenesis or progression of proliferative vitreoretinal disorders. This trial is registered with NCT00841334.

Insulin-like growth factor 1 (IGF-1 enhances the protein expression of CFTR.

Directory of Open Access Journals (Sweden)

Ha Won Lee

Full Text Available Low levels of insulin-like growth factor 1 (IGF-1 have been observed in the serum of cystic fibrosis (CF patients. However, the effects of low serum IGF-1 on the cystic fibrosis transmembrane conductance regulator (CFTR, whose defective function is the primary cause of cystic fibrosis, have not been studied. Here, we show in human cells that IGF-1 increases the steady-state levels of mature wildtype CFTR in a CFTR-associated ligand (CAL- and TC10-dependent manner; moreover, IGF-1 increases CFTR-mediated chloride transport. Using an acceptor photobleaching fluorescence resonance energy transfer (FRET assay, we have confirmed the binding of CAL and CFTR in the Golgi. We also show that CAL overexpression inhibits forskolin-induced increases in the cell-surface expression of CFTR. We found that IGF-1 activates TC10, and active TC10 alters the functional association between CAL and CFTR. Furthermore, IGF-1 and active TC10 can reverse the CAL-mediated reduction in the cell-surface expression of CFTR. IGF-1 does not increase the expression of ΔF508 CFTR, whose processing is arrested in the ER. This finding is consistent with our observation that IGF-1 alters the functional interaction of CAL and CFTR in the Golgi. However, when ΔF508 CFTR is rescued with low temperature or the corrector VRT-325 and proceeds to the Golgi, IGF-1 can increase the expression of the rescued ΔF508 CFTR. Our data support a model indicating that CAL-CFTR binding in the Golgi inhibits CFTR trafficking to the cell surface, leading CFTR to the degradation pathway instead. IGF-1-activated TC10 changes the interaction of CFTR and CAL, allowing CFTR to progress to the plasma membrane. These findings offer a potential strategy using a combinational treatment of IGF-1 and correctors to increase the post-Golgi expression of CFTR in cystic fibrosis patients bearing the ΔF508 mutation.

Maternal insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and IGF BP-3 and the hypertensive disorders of pregnancy.

LENUS (Irish Health Repository)

Cooley, Sharon M

2012-02-01

OBJECTIVE: To investigate the relationship between levels of insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and insulin-like growth factor binding protein 3 (IGFBP-3) in antenatal maternal serum and gestational hypertension and pre-eclampsia (PET). METHODS: Prospective cohort study of 1650 low-risk Caucasian women in a University teaching hospital in London. Statistical analysis was performed using commercial software (SPSS for Windows, version 6.1, SPSS, Chicago, IL), with P < 0.05 as significant. Maternal IGF 1, IGF 2 and IGF BP-3 were assessed on maternal blood at booking. Blood pressure was checked at each visit in conjunction with urine analysis. The Davey & MacGillivray 1988 classification system was used in making the diagnosis of PET. RESULTS: There was no significant correlation between maternal IGF-1 or IGFBP-3 levels and gestational hypertension or PET. However, a significant positive correlation does exist between maternal IGF-2 levels and PET. CONCLUSIONS: Maternal IGF-2 has a significant positive correlation with PET.

Analysis of the expression of putatively imprinted genes in bovine peri-implantation embryos

DEFF Research Database (Denmark)

Tveden-Nyborg, Pernille Yde; Alexopoulos, N.I.; Cooney, M.A.

2008-01-01

The application of assisted reproductive technologies (ART) has been shown to induce changes in the methylation of the embryonic genome, leading to aberrant gene expression, including that of imprinted genes. Aberrant methylation and gene expression has been linked to the large offspring syndrome...... (LOS) in bovine embryos resulting in increased embryonic morbidity and mortality. In the bovine, limited numbers of imprinted genes have been studied and studies have primarily been restricted to pre-implantation stages. This study reports original data on the expression pattern of 8 putatively...... imprinted genes (Ata3, Dlk1, Gnas, Grb10, Magel2, Mest-1, Ndn and Sgce) in bovine peri-implantation embryos. Two embryonic developmental stages were examined, Day 14 and Day 21. The gene expression pattern of single embryos was recorded for in vivo, in vitro produced (IVP) and parthenogenetic embryos...

IGF-IEc expression is increased in secondary compared to primary foci in neuroendocrine neoplasms.

Science.gov (United States)

Alexandraki, Krystallenia I; Philippou, Anastassios; Boutzios, Georgios; Theohari, Irini; Koutsilieris, Michael; Delladetsima, Ioanna Kassiani; Kaltsas, Gregory A

2017-10-03

Different Insulin-like growth factor-I (IGF-I) mRNA transcripts are produced by alternative splicing and particularly the IGF-IEc isoform has been implicated in the development and/or progression of various types of cancer. In the present study, we examined the potential role of IGF-IEc expression as a new immunohistochemical marker of aggressiveness in neuroendocrine neoplasms (NENs). We utilized immunohistochemical analysis in tissue specimens of 47 patients with NENs, to evaluate the expression of IGF-IEc (%) and Ki-67 proliferation index (%). Specimens from patients with tumors of different tissue origin, of either primary or metastatic lesions and of different grade were examined. Cytoplasmic IGF-IEc staining was found in 23 specimens of NENs or NECs: 10 pancreatic, 4 small bowel, 3 gastric, 1 lung, 1 uterine and 4 poorly differentiated of unknown primary origin. Ki-67 and IGF-IEc expression was positively correlated in all the samples studied (r=0.31, p=0.03). IGF-1Ec expression was more prevalent in specimens originating from metastatic foci with high Ki-67 compared to primary sites with low Ki-67 expression (p=0.036). These findings suggest a possible role of IGF-IEc in NEN tumorigenesis and progression to metastases that could be used as an additional new marker of a more aggressive behavior and a potential drugable target.

IGF-1 induces SOCS-2 but not SOCS-1 and SOCS-3 transcription in juvenile Nile tilapia (Oreochromis niloticus).

Science.gov (United States)

Liu, Cai-Zhi; Luo, Yuan; Limbu, Samwel Mchele; Chen, Li-Qiao; Du, Zhen-Yu

2018-05-20

Insulin-like growth factor-1 (IGF-1) plays a crucial role in regulating growth in vertebrates whereas suppressors of cytokine signaling (SOCS) act as feedback inhibitors of the GH/IGF-1 axis. Although SOCS-2 binds the IGF-1 receptor and inhibits IGF-1-induced STAT3 activation, presently there is no clear evidence as to whether IGF-1 could induce SOCS gene expression. The current study aimed to determine whether IGF-1 could induce the transcription of SOCS in juvenile Nile tilapia ( Oreochromis niloticus ). We show that there is a common positive relationship between the mRNA expression of IGF-I and SOCS-2 under different nutritional statuses and stimulants, but not the mRNA expression of SOCS-1 and SOCS-3 Furthermore, rhIGF-1 treatment and transcriptional activity assay confirmed the hypothesis that IGF-1 could induce SOCS-2 expression, whereas it had no effect or even decreased the expression of SOCS-1 and SOCS-3 Overall, we obtained evidence that the transcription of SOCS-2, but not SOCS-1 or SOCS-3, could be induced by IGF signaling, suggesting that SOCS-2 serves as a feedback suppressor of the IGF-1 axis in juvenile Nile tilapia. © 2018. Published by The Company of Biologists Ltd.

Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy.

Science.gov (United States)

Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F

2015-12-01

The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. Copyright © 2015 the American Physiological Society.

GH/IGF-I Transgene Expression on Muscle Homeostasis

Science.gov (United States)

Schwartz, Robert J.

1999-01-01

We propose to test the hypothesis that the growth hormone/ insulin like growth factor-I axis through autocrine/paracrine mechanisms may provide long term muscle homeostasis under conditions of prolonged weightlessness. As a key alternative to hormone replacement therapy, ectopic production of hGH, growth hormone releasing hormone (GHRH), and IGF-I will be studied for its potential on muscle mass impact in transgenic mice under simulated microgravity. Expression of either hGH or IGF-I would provide a chronic source of a growth-promoting protein whose biosynthesis or secretion is shut down in space. Muscle expression of the IGF-I transgene has demonstrated about a 20% increase in hind limb muscle mass over control nontransgenic litter mates. These recent experiments, also establish the utility of hind-limb suspension in mice as a workable model to study atrophy in weight bearing muscles. Thus, transgenic mice will be used in hind-limb suspension models to determine the role of GH/IGF-I on maintenance of muscle mass and whether concentric exercises might act in synergy with hormone treatment. As a means to engineer and ensure long-term protein production that would be workable in humans, gene therapy technology will be used by to monitor muscle mass preservation during hind-limb suspension, after direct intramuscular injection of a genetically engineered muscle-specific vector expressing GHRH. Effects of this gene-based therapy will be assessed in both fast twitch (medial gastrocnemius) and slow twitch muscle (soleus). End-points include muscle size, ultrastructure, fiber type, and contractile function, in normal animals, hind limb suspension, and reambutation.

A Loss-of-Function Splice Acceptor Variant in IGF2 Is Protective for Type 2 Diabetes.

Science.gov (United States)

Mercader, Josep M; Liao, Rachel G; Bell, Avery D; Dymek, Zachary; Estrada, Karol; Tukiainen, Taru; Huerta-Chagoya, Alicia; Moreno-Macías, Hortensia; Jablonski, Kathleen A; Hanson, Robert L; Walford, Geoffrey A; Moran, Ignasi; Chen, Ling; Agarwala, Vineeta; Ordoñez-Sánchez, María Luisa; Rodríguez-Guillen, Rosario; Rodríguez-Torres, Maribel; Segura-Kato, Yayoi; García-Ortiz, Humberto; Centeno-Cruz, Federico; Barajas-Olmos, Francisco; Caulkins, Lizz; Puppala, Sobha; Fontanillas, Pierre; Williams, Amy L; Bonàs-Guarch, Sílvia; Hartl, Chris; Ripke, Stephan; Tooley, Katherine; Lane, Jacqueline; Zerrweck, Carlos; Martínez-Hernández, Angélica; Córdova, Emilio J; Mendoza-Caamal, Elvia; Contreras-Cubas, Cecilia; González-Villalpando, María E; Cruz-Bautista, Ivette; Muñoz-Hernández, Liliana; Gómez-Velasco, Donaji; Alvirde, Ulises; Henderson, Brian E; Wilkens, Lynne R; Le Marchand, Loic; Arellano-Campos, Olimpia; Riba, Laura; Harden, Maegan; Gabriel, Stacey; Abboud, Hanna E; Cortes, Maria L; Revilla-Monsalve, Cristina; Islas-Andrade, Sergio; Soberon, Xavier; Curran, Joanne E; Jenkinson, Christopher P; DeFronzo, Ralph A; Lehman, Donna M; Hanis, Craig L; Bell, Graeme I; Boehnke, Michael; Blangero, John; Duggirala, Ravindranath; Saxena, Richa; MacArthur, Daniel; Ferrer, Jorge; McCarroll, Steven A; Torrents, David; Knowler, William C; Baier, Leslie J; Burtt, Noel; González-Villalpando, Clicerio; Haiman, Christopher A; Aguilar-Salinas, Carlos A; Tusié-Luna, Teresa; Flannick, Jason; Jacobs, Suzanne B R; Orozco, Lorena; Altshuler, David; Florez, Jose C

2017-11-01

Type 2 diabetes (T2D) affects more than 415 million people worldwide, and its costs to the health care system continue to rise. To identify common or rare genetic variation with potential therapeutic implications for T2D, we analyzed and replicated genome-wide protein coding variation in a total of 8,227 individuals with T2D and 12,966 individuals without T2D of Latino descent. We identified a novel genetic variant in the IGF2 gene associated with ∼20% reduced risk for T2D. This variant, which has an allele frequency of 17% in the Mexican population but is rare in Europe, prevents splicing between IGF2 exons 1 and 2. We show in vitro and in human liver and adipose tissue that the variant is associated with a specific, allele-dosage-dependent reduction in the expression of IGF2 isoform 2. In individuals who do not carry the protective allele, expression of IGF2 isoform 2 in adipose is positively correlated with both incidence of T2D and increased plasma glycated hemoglobin in individuals without T2D, providing support that the protective effects are mediated by reductions in IGF2 isoform 2. Broad phenotypic examination of carriers of the protective variant revealed no association with other disease states or impaired reproductive health. These findings suggest that reducing IGF2 isoform 2 expression in relevant tissues has potential as a new therapeutic strategy for T2D, even beyond the Latin American population, with no major adverse effects on health or reproduction. © 2017 by the American Diabetes Association.

Efficient and sustained IGF-1 expression in the adipose tissue-derived stem cells mediated via a lentiviral vector.

Science.gov (United States)

Chen, Ting; Huang, Dangsheng; Chen, Guanghui; Yang, Tingshu; Yi, Jun; Tian, Miao

2015-02-01

The adipose tissue-derived stem cells (ADSCs) represent a significant area of the cell therapy. Genetic modification of ADSCs may further improve their therapeutic potential. Here, we aimed to generate a lentiviral vector expressing insulin-like growth factor-I (IGF-1) and investigate the impact of IGF-1 transduction on the properties of cultured ADSCs. Isolated rat ADSCs were assessed by flow cytometric analysis. IGF-1 was cloned and inserted into the pLenO-DCE plasmid to acquire pLenO-DCE-IGF-1 plasmid. Lentivirus was enveloped with pRsv-REV, pMDlg-pRRE and pMD2G plasmids in 293T cells. The ADSCs were transfected with the vectors. And then IGF-1-induced anti-apoptosis was evaluated by annexin V-FITC. Besides, proliferation of cells was detected by MTT assay and EdU. Moreover, Akt phosphorylation was evaluated by Western blotting analysis. Stable expression of IGF-1 in ADSCs was confirmed. ADSCs were positive for CD90 and CD29, but negative for CD31, CD34 and CD45. The transduction of IGF-1 to the ADSCs caused a dramatic increase in P-Akt expression. Over-expression of IGF-1 in ADSCs could improve the paracine of IGF-1 in a time-dependent manner, but could not promote the proliferation of ADSCs. This study indicated that lentiviral vectors offered a promising mean of delivering IGF-1 to the ADSCs. Lentiviral-mediated over-expression of therapeutic IGF-1 gene in ADSCs could prolong the anti-apoptosis effect of IGF-1, which might be induced by the activation of the PI3K/Akt pathway. And our data would improve the efficacy of ADSC-based therapies.

Increased cardiogenesis in P19-GFP teratocarcinoma cells expressing the propeptide IGF-1Ea

Energy Technology Data Exchange (ETDEWEB)

Poudel, Bhawana [Heart Science Centre, National Heart and Lung Institute, Imperial College, London (United Kingdom); Bilbao, Daniel [EMBL, Mouse Biology Unit, Monterotondo (Italy); Sarathchandra, Padmini; Germack, Renee [Heart Science Centre, National Heart and Lung Institute, Imperial College, London (United Kingdom); Rosenthal, Nadia [Heart Science Centre, National Heart and Lung Institute, Imperial College, London (United Kingdom); Australian Regenerative Medicine Institute, Monash University, Melbourne (Australia); Santini, Maria Paola, E-mail: m.santini@imperial.ac.uk [Heart Science Centre, National Heart and Lung Institute, Imperial College, London (United Kingdom)

2011-12-16

Highlights: Black-Right-Pointing-Pointer In this study, we explored the function of IGF-1Ea propeptide in inducing cardiogenesis of stem cells. Black-Right-Pointing-Pointer IGF-1Ea promoted cardiac mesodermal induction in uncommitted cells. Black-Right-Pointing-Pointer Under differentiation condition, IGF-1Ea increased expression of cardiac differentiation markers. Black-Right-Pointing-Pointer Furthermore, it promoted formation of finely organized sarcomeric structure. Black-Right-Pointing-Pointer IGF-1Ea propeptide may be a good candidate to improve production of cardiomyocytes from pluripotent cells. -- Abstract: The mechanism implicated in differentiation of endogenous cardiac stem cells into cardiomyocytes to regenerate the heart tissue upon an insult remains elusive, limiting the therapeutical goals to exogenous cell injection and/or gene therapy. We have shown previously that cardiac specific overexpression of the insulin-like growth factor 1 propeptide IGF-1Ea induces beneficial myocardial repair after infarct. Although the mechanism is still under investigation, the possibility that this propeptide may be involved in promoting stem cell differentiation into the cardiac lineage has yet to be explored. To investigate whether IGF-1Ea promote cardiogenesis, we initially modified P19 embryonal carcinoma cells to express IGF-1Ea. Taking advantage of their cardiomyogenic nature, we analyzed whether overexpression of this propeptide affected cardiac differentiation program. The data herein presented showed for the first time that constitutively overexpressed IGF-1Ea increased cardiogenic differentiation program in both undifferentiated and DMSO-differentiated cells. In details, IGF-1Ea overexpression promoted localization of alpha-actinin in finely organized sarcomeric structure compared to control cells and upregulated the cardiac mesodermal marker NKX-2.5 and the ventricular structural protein MLC2v. Furthermore, activated IGF-1 signaling promoted cardiac

Increased cardiogenesis in P19-GFP teratocarcinoma cells expressing the propeptide IGF-1Ea

International Nuclear Information System (INIS)

Poudel, Bhawana; Bilbao, Daniel; Sarathchandra, Padmini; Germack, Renee; Rosenthal, Nadia; Santini, Maria Paola

2011-01-01

Highlights: ► In this study, we explored the function of IGF-1Ea propeptide in inducing cardiogenesis of stem cells. ► IGF-1Ea promoted cardiac mesodermal induction in uncommitted cells. ► Under differentiation condition, IGF-1Ea increased expression of cardiac differentiation markers. ► Furthermore, it promoted formation of finely organized sarcomeric structure. ► IGF-1Ea propeptide may be a good candidate to improve production of cardiomyocytes from pluripotent cells. -- Abstract: The mechanism implicated in differentiation of endogenous cardiac stem cells into cardiomyocytes to regenerate the heart tissue upon an insult remains elusive, limiting the therapeutical goals to exogenous cell injection and/or gene therapy. We have shown previously that cardiac specific overexpression of the insulin-like growth factor 1 propeptide IGF-1Ea induces beneficial myocardial repair after infarct. Although the mechanism is still under investigation, the possibility that this propeptide may be involved in promoting stem cell differentiation into the cardiac lineage has yet to be explored. To investigate whether IGF-1Ea promote cardiogenesis, we initially modified P19 embryonal carcinoma cells to express IGF-1Ea. Taking advantage of their cardiomyogenic nature, we analyzed whether overexpression of this propeptide affected cardiac differentiation program. The data herein presented showed for the first time that constitutively overexpressed IGF-1Ea increased cardiogenic differentiation program in both undifferentiated and DMSO-differentiated cells. In details, IGF-1Ea overexpression promoted localization of alpha-actinin in finely organized sarcomeric structure compared to control cells and upregulated the cardiac mesodermal marker NKX-2.5 and the ventricular structural protein MLC2v. Furthermore, activated IGF-1 signaling promoted cardiac mesodermal induction in undifferentiated cells independently of cell proliferation. This analysis suggests that IGF-1Ea may be a

Nuclear transfer alters placental gene expression and associated histone modifications of the placental-specific imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2) in cattle.

Science.gov (United States)

Arnold, Daniel R; Gaspar, Roberta C; da Rocha, Carlos V; Sangalli, Juliano R; de Bem, Tiago H C; Corrêa, Carolina A P; Penteado, João C T; Meirelles, Flavio V; Lopes, Flavia L

2017-03-01

Abnormal placental development is frequent in nuclear transfer (NT) pregnancies and is likely to be associated with altered epigenetic reprogramming. In the present study, fetal and placental measurements were taken on Day 60 of gestation in cows with pregnancies produced by AI, IVF and NT. Placentas were collected and subjected to histological evaluation, the expression of genes important in trophoblast differentiation and expression of the placental imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2), as well as chromatin immunoprecipitation (ChIP) for histone marks within the promoter of PHLDA2. Fewer binucleated cells were observed in NT cotyledons, followed by IVF and AI cotyledons (P<0.05). Expression of heart and neural crest derivatives expressed 1 (HAND1), placental lactogen (PL), pregnancy-associated glycoprotein 9 (PAG-9) and PHLDA2 was elevated in NT cotyledons compared with AI cotyledons. Expression of PHLDA2 was higher in IVF than AI samples (P<0.05). ChIP revealed an increase in the permissive mark dimethylation of lysine 4 on histone H3 (H3K4me2), surprisingly associated with the silent allele of PHLDA2, and a decrease in the inhibitory mark H3K9me2 in NT samples. Thus, genes critical for placental development were altered in NT placentas, including an imprinted gene. Allele-specific changes in the permissive histone mark in the PHLDA2 promoter indicate misregulation of imprinting in clones. Abnormal trophoblast differentiation could have resulted in lower numbers of binucleated cells following NT. These results suggest that the altered expression of imprinted genes associated with NT are also caused by changes in histone modifications.

Maternal nutrient restriction in mid-to-late gestation influences fetal mRNA expression in muscle tissues in beef cattle.

Science.gov (United States)

Paradis, Francois; Wood, Katie M; Swanson, Kendall C; Miller, Stephen P; McBride, Brian W; Fitzsimmons, Carolyn

2017-08-18

Manipulating maternal nutrition during specific periods of gestation can result in re-programming of fetal and post-natal development. In this experiment we investigated how a feed restriction of 85% compared with 140% of total metabolizable energy requirements, fed to cows during mid-to-late gestation, influences phenotypic development of fetuses and mRNA expression of growth (Insulin-Like Growth Factor family and Insulin Receptor (INSR)), myogenic (Myogenic Differentiation 1 (MYOD1), Myogenin (MYOG), Myocyte Enhancer Factor 2A (MEF2A), Serum Response Factor (SRF)) and adipogenic (Peroxisome Proliferator Activated Receptor Gamma (PPARG)) genes in fetal longissimus dorsi (LD) and semitendinosus (ST) muscle. DNA methylation of imprinted genes, Insulin Like Growth Factor 2 (IGF2) and Insulin Like Growth Factor 2 Receptor (IGF2R), and micro RNA (miRNA) expression, were also examined as potential consequences of poor maternal nutrition, but also potential regulators of altered gene expression patterns. While the nutrient restriction impacted dam body weight, no differences were observed in phenotypic fetal measurements (weight, crown-rump length, or thorax circumference). Interestingly, LD and ST muscles responded differently to the differential pre-natal nutrient levels. While LD muscle of restricted fetal calves had greater mRNA abundances for Insulin Like Growth Factor 1 and its receptor (IGF1 and IGF1R), IGF2R, INSR, MYOD1, MYOG, and PPARG, no significant differences were observed for gene expression in ST muscle. Similarly, feed restriction had a greater impact on the methylation level of IGF2 Differentially Methylated Region 2 (DMR2) in LD muscle as compared to ST muscle between treatment groups. A negative correlation existed between IGF2 mRNA expression and IGF2 DMR2 methylation level in both LD and ST muscles. Differential expression of miRNAs 1 and 133a were also detected in LD muscle. Our data suggests that a nutrient restriction of 85% as compared to 140

IGF2BP3 Modulates the Interaction of Invasion-Associated Transcripts with RISC

Directory of Open Access Journals (Sweden)

Hanane Ennajdaoui

2016-05-01

Full Text Available Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3 expression correlates with malignancy, but its role(s in pathogenesis remains enigmatic. We interrogated the IGF2BP3-RNA interaction network in pancreatic ductal adenocarcinoma (PDAC cells. Using a combination of genome-wide approaches, we have identified 164 direct mRNA targets of IGF2BP3. These transcripts encode proteins enriched for functions such as cell migration, proliferation, and adhesion. Loss of IGF2BP3 reduced PDAC cell invasiveness and remodeled focal adhesion junctions. Individual nucleotide resolution crosslinking immunoprecipitation (iCLIP revealed significant overlap of IGF2BP3 and microRNA (miRNA binding sites. IGF2BP3 promotes association of the RNA-induced silencing complex (RISC with specific transcripts. Our results show that IGF2BP3 influences a malignancy-associated RNA regulon by modulating miRNA-mRNA interactions.

IGF2BP3 Modulates the Interaction of Invasion-Associated Transcripts with RISC.

Science.gov (United States)

Ennajdaoui, Hanane; Howard, Jonathan M; Sterne-Weiler, Timothy; Jahanbani, Fereshteh; Coyne, Doyle J; Uren, Philip J; Dargyte, Marija; Katzman, Sol; Draper, Jolene M; Wallace, Andrew; Cazarez, Oscar; Burns, Suzanne C; Qiao, Mei; Hinck, Lindsay; Smith, Andrew D; Toloue, Masoud M; Blencowe, Benjamin J; Penalva, Luiz O F; Sanford, Jeremy R

2016-05-31

Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) expression correlates with malignancy, but its role(s) in pathogenesis remains enigmatic. We interrogated the IGF2BP3-RNA interaction network in pancreatic ductal adenocarcinoma (PDAC) cells. Using a combination of genome-wide approaches, we have identified 164 direct mRNA targets of IGF2BP3. These transcripts encode proteins enriched for functions such as cell migration, proliferation, and adhesion. Loss of IGF2BP3 reduced PDAC cell invasiveness and remodeled focal adhesion junctions. Individual nucleotide resolution crosslinking immunoprecipitation (iCLIP) revealed significant overlap of IGF2BP3 and microRNA (miRNA) binding sites. IGF2BP3 promotes association of the RNA-induced silencing complex (RISC) with specific transcripts. Our results show that IGF2BP3 influences a malignancy-associated RNA regulon by modulating miRNA-mRNA interactions. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Coordinated increase in skeletal muscle fiber area and expression of IGF-I with resistance exercise in elderly post-operative patients

DEFF Research Database (Denmark)

Suetta, Charlotte; Clemmensen, Christoffer; Andersen, Jesper L

2010-01-01

Hypertrophy of developing skeletal muscle involves stimulation by insulin-like growth factor-I (IGF-I), however, the role of IGF-I in adult muscle is less clarified. In the present study, the mRNA splice variants of IGF-I (IGF-IEa and MGF) and the changes in muscle fiber cross sectional area after...... and in addition induces marked increases in the expression of IGF-I splice variants, supporting the idea that IGF-I is involved in regulating muscle hypertrophy.......-operated-side served as a within subject control. Muscle biopsies were obtained from the vastus lateralis of both limbs at +2d post-operative (baseline), at 5weeks and 12weeks post-surgery to analyze for changes in type 1 and type 2 muscle fiber area. Changes in expression levels of IGF-I mRNA isoforms were determined...

MVP expression is related to IGF1-R in cervical carcinoma patients treated by radiochemotherapy.

Science.gov (United States)

Lloret, Marta; Lara, Pedro Carlos; Bordón, Elisa; Rey, Agustin; Falcón, Orlando; Apolinario, Rosa Maria; Clavo, Bernardino; Ruiz, Ana

2008-09-01

To assess the expression of MVP in cervix carcinoma patients treated by radiochemotherapy, its relation to clinical and pathologic prognostic factors and its role in predicting clinical outcome. In addition the relation to IGF-1R expression in this cohort of patients will be explored. Sixty consecutive patients suffering from localized cervix carcinoma were prospectively included in this study from July 1999 to December 2003. Follow-up was closed in November 2007. Patients were staged following the TNM classification. All patients received pelvic radiation (45-64.80 Gy in 1.8-2 Gy fractions) followed brachytherapy and concomitant cisplatin at 40 mg/m(2)/week doses. MVP expression was studied by immunohistochemistry in paraffin-embedded tumour tissue. MVP was expressed in 58 patients (96.7%) and no relation was found with clinicopathological variables. High MVP expression was related to high IGF1-R expression (p=0.023). Complete response after treatment was observed in 50 patients (83.3%). Clinical stage of the disease and clinical response to radiochemotherapy were the most important prognostic factors related to survival. High MVP and IGF-1R tumour expression was strongly related to poor local and regional disease-free survival (p=0.006), distant disease-free survival (p=0.050), disease-free survival (p=0.006), and cause-specific survival (p=0.007) in patients achieving a complete response. MVP and IGF-1R expression were related in clinical cervical tumours and confer reduced long-term local control in patients who achieved clinical complete response to radiochemotherapy.

Association of tRNA methyltransferase NSUN2/IGF-II molecular signature with ovarian cancer survival.

Science.gov (United States)

Yang, Jia-Cheng; Risch, Eric; Zhang, Meiqin; Huang, Chan; Huang, Huatian; Lu, Lingeng

2017-09-01

To investigate the association between NSUN2/IGF-II signature and ovarian cancer survival. Using a publicly accessible dataset of RNA sequencing and clinical follow-up data, we performed Classification and Regression Tree and survival analyses. Patients with NSUN2 high IGF-II low had significantly superior overall and disease progression-free survival, followed by NSUN2 low IGF-II low , NSUN2 high IGF-II high and NSUN2 low IGF-II high (p IGF-II signature with the risks of death and relapse remained significant in multivariate Cox regression models. Random-effects meta-analyses show the upregulated NSUN2 and IGF-II expression in ovarian cancer versus normal tissues. The NSUN2/IGF-II signature associates with heterogeneous outcome and may have clinical implications in managing ovarian cancer.

Organ-Specific and Age-Dependent Expression of Insulin-like Growth Factor-I (IGF-I) mRNA Variants: IGF-IA and IB mRNAs in the Mouse

OpenAIRE

Ohtsuki, Takashi; Otsuki, Mariko; Murakami, Yousuke; Maekawa, Tetsuya; Yamamoto, Takashi; Akasaka, Koji; Takeuchi, Sakae; Takahashi, Sumio

2005-01-01

Insulin-like growth factor-I (IGF-I) gene generates several IGF-I mRNA variants by alternative splicing. Two promoters are present in mouse IGF-I gene. Each promoter encodes two IGF-I mRNA variants (IGF-IA and IGF-IB mRNAs). Variants differ by the presence (IGF-IB) or absence (IGF-IA) of a 52-bp insert in the E domain-coding region. Functional differences among IGF-I mRNAs, and regulatory mechanisms for alternative splicing of IGF-I mRNA are not yet known. We analyzed the expression of mouse ...

IGF2BP3 as a potential tissue marker for the diagnosis of esophageal high-grade intraepithelial neoplasia

Directory of Open Access Journals (Sweden)

Zhang JJ

2017-08-01

Full Text Available Jingjing Zhang,1,* Qing Ji,2,* Chunhua Jiao,3,* Lihua Ren,4 Ye Zhao,4 Yanfang Chen,4 Ruihua Shi,4 Yadong Feng4 1State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing, 2Department of Emergency, Jingjiang People’s Hospital, Jingjiang, 3Department of Gastroenterology, First Affiliated Hospital with Nanjing Medical University, 4Department of Gastroenterology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, People’s Republic of China *These authors contributed equally to this work Background: The clinical significance of insulin-like growth factor-II mRNA-binding protein-3 (IGF2BP3 in esophageal high-grade intraepithelial neoplasia (HGIN is not clear. This study was designed to characterize the expression of IGF2BP3 in HGIN. Patients and methods: IGF2BP3 expression was evaluated by Western blot analyses in 12 cases and by immunohistochemistry (IHC in 112 cases. The associations between IGF2BP3 expression in HGIN and the clinicopathological parameters were examined. Results: Moderate to strong IGF2BP3 expression was present in HGIN samples. Using IHC, it was found that IGF2BP3 was positive in 68 (60.71% cases. Intense IHC of IGF2BP3 in HGIN was associated with a deeper lesion depth, and the lesion depth was the only predictor of the positive expression of IGF2BP3. Conclusion: Our results suggested that IGF2BP3 may be a supplementary tissue marker for preoperative diagnosis of HGIN. Keywords: esophageal squamous cell carcinoma, precancerous lesion, immunohistochemistry detection, early diagnosis

The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

Energy Technology Data Exchange (ETDEWEB)

Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Hidalgo, Cecilia [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Lavandero, Sergio, E-mail: slavander@uchile.cl [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile)

2009-10-09

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal {alpha}-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

International Nuclear Information System (INIS)

Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo; Hidalgo, Cecilia; Lavandero, Sergio

2009-01-01

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal α-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

Branchial expression and localization of the insulin-like growth factor 1 (IGF-1) receptor and changes in plasma IGF-1 and IGF-1 binding protein in striped bass during salinity acclimation

DEFF Research Database (Denmark)

Tipsmark, Christian Kølbæk; Madsen, Steffen; Borski, Russell

2006-01-01

In euryhaline teleosts the insulin-like growth factor 1 (IGF-1)/growth hormone axis is known to affect salinity tolerance and gill Na,K-ATPase activity. However, virtually nothing is known on expression and cellular localization of the IGF-1 receptor (IGF-1R) in the teleost gill during salinity a...

Interaction of IGF2 and PTEN in ( M alignant Breast T issues

Directory of Open Access Journals (Sweden)

Preetha J Shetty

2012-07-01

Full Text Available Background: Breast Cancer (BC is one of the leading malignancies affecting women worldwide. Epigenetic mechanisms regulate gene expression playing an important role in the pathophysiology of cancer. In the present study IGF2 and PTEN genes in AKT pathway were selected for evaluation. Objective: To investigate the role of methylation and interaction of IGF2 and PTEN and in the pathoetiology of BC. Methods: Paraffin embedded archival breast tumor and adjacent normal tissue samples were used for carrying out PCR based methylation assay, genomic PCR, immunohistochemistry and qRT PCR. Results: In-Silico study indicated the absence of hormone responsive elements in the promoters of the selected genes. Methylation results indicated significant loss of methylation in IGF2 exon 9 CpG cluster and significant gain of PTEN promoter methylation in tumors. Immunohistochemistry revealed enhanced cytoplasmic expression o f IGF2 protein (p< 0.0001 and decreased nuclear localization of PTEN protein (p=0.0069 in the breast tumors. RT-PCR results indicated an increased IGF2 (p=0.024 and decreased PTEN transcripts (p<0.0001 in the tumors. Conclusion: Increased IGF2 in normal tissues increases PTEN which acts as a negative regulator of AKT pathway in the cytoplasm controlling excessive proliferation while in tumors this regulation is lost. PTEN acts as a negative regulator of MAPK pathway in the nucleus, plays an important role in cell cycle arrest in normal breast tissue. Reduction of PTEN in tumor tissue affects this pathway leading to cell survival. IGF2 and PTEN have a role in breast cancer and these molecular factors can be used for targeting therapy in future.

Risk factors for breast cancer and expression of insulin-like growth factor-2 (IGF-2 in women with breast cancer in Wuhan City, China.

Directory of Open Access Journals (Sweden)

Jun Qiu

Full Text Available PURPOSE: The purpose of this study was to explore the risk factors for breast cancer and establish the expression rate of IGF-2 in female patients. METHODS: A case control study with 500 people in case group and 500 people in control group. A self-administered questionnaire was used to investigate risk factors for breast cancer. All cases were interviewed during a household survey. Immune-histochemical method was used to inspect the expression of IGF-2 in different tissues (benign breast lesions, breast cancer and tumor-adjacent tissue. RESULTS: Multivariate adjusted odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. High body mass index (OR = 1.012,95%CI = 1.008-1.016, working attributes (OR = 1.004, 95%CI = 1.002 = 1.006, long menstrual period (OR = 1.007, 95%CI = 1.005-1.009, high parity OR = 1.003, 95%CI = 1.001-1.005 , frequent artificial abortion (OR = 1.004, 95%CI = 1.001-1.005, family history of cancer (OR = 1.003, 95%CI = 1.000-1.005, period of night shift (OR = 1.003, 95%CI = 1.001-1.006, live in high risk environment (OR = 1.005, 95%CI = 1.002-1.008, and family problems (OR = 1.010, 95%CI = 1.005-1.014 were associated with increased risk for breast cancer. In this study, good sleeping status, positive coping strategies, subjective support, and utility degree of social support were associated with reduced risk for breast cancer (OR = 0.998, 0.997, 0.985, 0.998 respectively; 95%CI = 0.996-1.000, 0.994-1.000, 0.980-0.989, 0.996-1.000, respectively. In benign breast lesions, breast cancer and tumor-adjacent tissue, IGF-2 was mainly expressed in the cytoplasm, but its expression rate was different (p<0.05. CONCLUSIONS: The incidence of breast cancer is a common result of multiple factors. IGF-2 is involved in the development of breast cancer, and its expression varies in different tissues (benign breast lesions

BCL-2, in combination with MVP and IGF-1R expression, improves prediction of clinical outcome in complete response cervical carcinoma patients treated by radiochemotherapy.

Science.gov (United States)

Henríquez-Hernández, Luis Alberto; Lloret, Marta; Pinar, Beatriz; Bordón, Elisa; Rey, Agustín; Lubrano, Amina; Lara, Pedro Carlos

2011-09-01

To investigate whether BCL-2 expression would improve MVP/IGF-1R prediction of clinical outcome in cervix carcinoma patients treated by radiochemotherapy, and suggest possible mechanisms behind this effect. Fifty consecutive patients, who achieved complete response to treatment, from a whole series of 60 cases suffering from non-metastatic localized cervical carcinoma, were prospectively included in this study from July 1999 to December 2003. Follow-up was closed in January 2011. All patients received pelvic radiation (45-64.80 Gy in 1.8-2 Gy fractions) with concomitant cisplatin at 40 mg/m2/week doses followed by brachytherapy. Oncoprotein expression was studied by immunohistochemistry in paraffin-embedded tumour tissue. No relation was found between BCL-2 and clinicopathological variables. High MVP/IGF-1R/BCL-2 tumour expression was strongly related to poor local and regional disease-free survival (PMVP, and IGF-1R overexpression were related to poorer clinical outcome in cervical cancer patients who achieved clinical complete response to radiochemotherapy. The NHEJ repair protein Ku70/80 expression could be involved in the regulation of these oncoproteins. Copyright © 2011 Elsevier Inc. All rights reserved.

The insulin-like growth factor 2 (IGF2) gene intron3-g.3072G>A polymorphism is not the only Sus scrofa chromosome 2p mutation affecting meat production and carcass traits in pigs: evidence from the effects of a cathepsin D (CTSD) gene polymorphism.

Science.gov (United States)

Fontanesi, L; Speroni, C; Buttazzoni, L; Scotti, E; Dall'Olio, S; Nanni Costa, L; Davoli, R; Russo, V

2010-07-01

Large White animals carrying the homozygous genotype IGF2 intron3-g.3072GG, and by haplotype analysis between the markers of the 2 considered genes in the complete data set. Overall, these results indicate that the IGF2 intron3-g.3072G>A mutation is not the only polymorphism affecting fatness and muscle deposition on SSC2p. Therefore, the CTSD g.70G>A polymorphism could be used to increase selection efficiency in marker-assisted selection programs that already use the IGF2 mutation. However, for practical applications, because the CTSD gene should not be imprinted (we obtained this information from expression analysis in adult skeletal muscle), the different modes of inheritance of the 2 genes have to be considered.

Prophylactic Subacute Administration of Zinc Increases CCL2, CCR2, FGF2, and IGF-1 Expression and Prevents the Long-Term Memory Loss in a Rat Model of Cerebral Hypoxia-Ischemia

Directory of Open Access Journals (Sweden)

Victor Manuel Blanco-Alvarez

2015-01-01

Full Text Available Prophylactic subacute administration of zinc decreases lipoperoxidation and cell death following a transient cerebral hypoxia-ischemia, thus suggesting neuroprotective and preconditioning effects. Chemokines and growth factors are also involved in the neuroprotective effect in hypoxia-ischemia. We explored whether zinc prevents the cerebral cortex-hippocampus injury through regulation of CCL2, CCR2, FGF2, and IGF-1 expression following a 10 min of common carotid artery occlusion (CCAO. Male rats were grouped as follows: (1 Zn96h, rats injected with ZnCl2 (one dose every 24 h during four days; (2 Zn96h + CCAO, rats treated with ZnCl2 before CCAO; (3 CCAO, rats with CCAO only; (4 Sham group, rats with mock CCAO; and (5 untreated rats. The cerebral cortex-hippocampus was dissected at different times before and after CCAO. CCL2/CCR2, FGF2, and IGF-1 expression was assessed by RT-PCR and ELISA. Learning in Morris Water Maze was achieved by daily training during 5 days. Long-term memory was evaluated on day 7 after learning. Subacute administration of zinc increased expression of CCL2, CCR2, FGF2, and IGF-1 in the early and late phases of postreperfusion and prevented the CCAO-induced memory loss in the rat. These results might be explained by the induction of neural plasticity because of the expression of CCL2 and growth factors.

Genomic imprinting status of IGF-II and H19 in placentas of fetal ...

Indian Academy of Sciences (India)

velop metabolic syndrome later in life, manifesting as obe- ... Venous blood samples were collected from both the parents .... and five families of the group B2 were informative for H19. .... that may have impacts on the imprinting status of imprinted genes ... This work was supported by a grant from National Natural Science.

IGF2BP3 functions as a potential oncogene and is a crucial target of miR-34a in gastric carcinogenesis.

Science.gov (United States)

Zhou, Yuhang; Huang, Tingting; Siu, Ho Lam; Wong, Chi Chun; Dong, Yujuan; Wu, Feng; Zhang, Bin; Wu, William K K; Cheng, Alfred S L; Yu, Jun; To, Ka Fai; Kang, Wei

2017-04-11

Gastric cancer (GC) is one of the frequent causes of cancer-related death in eastern Asian population. IGF2BP2 lists in the top rank up-regulated genes in GC, but its functional role is unclear. The expression of IGF2BP3 in GC cell lines and primary samples was examined by qRT-PCR and Western blot. The biological role of IGF2BP3 was revealed by a series of functional in vitro studies. Its regulation by microRNAs (miRNAs) was predicted by TargetScan and confirmed by luciferase assays and rescue experiments. IGF2BP3 ranked the No.1 of the up-regulated genes by expression microarray analysis in GC cell lines. The expression level of IGF2BP3 was observed in GC tissues comparing with non-tumorous gastric epitheliums. The up-regulated IGF2BP3 expression was associated with poor disease specific survival. IGF2BP3 knockdown significantly inhibited cell proliferation and invasion. Apart from copy number gain, IGF2BP3 has been confirmed to be negatively regulated by tumor-suppressive miRNA, namely miR-34a. The expression of miR-34a showed negative correlation with IGF2BP3 mRNA expression in primary GC samples and more importantly, re-overexpression of IGF2BP3 rescued the inhibitory effect of miR-34a. We compressively revealed the oncogenic role of IGF2BP3 in gastric tumorigenesis and confirmed its activation is partly due to the silence of miR-34a. Our findings identified useful prognostic biomarker and provided clinical translational potential.

Altered expression of IGF-I system in neurons of the inflamed spinal cord during acute experimental autoimmune encephalomyelitis.

Science.gov (United States)

Parvaneh Tafreshi, Azita; Talebi, Farideh; Ghorbani, Samira; Bernard, Claude; Noorbakhsh, Farshid

2017-10-01

There is growing evidence that the impaired IGF-I system contributes to neurodegeneration. In this study, we examined the spinal cords of the EAE, the animal model of multiple sclerosis, to see if the expression of the IGF-I system is altered. To induce EAE, C57/BL6 mice were immunized with the Hooke lab MOG kit, sacrificed at the peak of the disease and their spinal cords were examined for the immunoreactivities (ir) of the IGF-I, IGF binding protein-1 (IGFBP-1) and glycogen synthase kinase 3β (GSK3β), as one major downstream molecule in the IGF-I signaling. Although neurons in the non EAE spinal cords did not show the IGF-I immunoreactivity, they were numerously positive for the IGFBP-1. In the inflamed EAE spinal cord however, the patterns of expressions were reversed, that is, a significant increased number of IGF-I expressing neurons versus a reduced number of IGFBP-1 positive neurons. Moreover, while nearly all IGF-I-ir neurons expressed GSK3β, some expressed it more intensely. Considering our previous finding where we showed a significant reduced number of the inactive (phosphorylated) but not that of the total GSK3β expressing neurons in the EAE spinal cord, it is conceivable that the intense total GSK3β expression in the IGF-I-ir neurons belongs to the active form of GSK3β known to exert neuroinflammatory effects. We therefore suggest that the altered expression of the IGF-I system including GSK3β in spinal cord neurons might involve in pathophysiological events during the EAE. © 2017 Wiley Periodicals, Inc.

Alternative splicing and expression of the insulin-like growth factor (IGF-1) gene in osteoblasts under mechanical stretch

Institute of Scientific and Technical Information of China (English)

XIAN Chengyu; WANG Yuanliang; ZHANG Bingbing; TANG Liling; PAN Jun; LUO Yanfeng; JIANG Peng; LI Dajun

2006-01-01

Insulin-like growth factor 1 (IGF-1) promotes osteoblasts differentiation and bone formation,and its expression is induced by mechanical stretch,thus IGF-1 has been considered an effector molecule that links mechanical stimulation and local tissue responses. In this study, a mechanical stretching device was designed to apply physiological level static or cyclic stretching stimulation to osteoblasts.Different isoforms of IGF-1 mRNA were amplified by RT-PCR from the cells using respective primers and these amplified products were sequenced. An isoform of IGF-1 splicing product was found to be selectively produced by osteoblasts under stretching stimulation. This IGF-1 isoform had identical sequence with the mechano growth factor (MGF) which was originally identified in muscle cells. Regulations of the expression of the liver-type IGF (L.IGF-1) and MGF in osteoblasts under stretch stimulation were further studied using semi-quantitative RT-PCR.Stretch stimulation was found to promot the expression of IGF-1 (L.IGF-1 and MGF), and for both isoforms expression was more effectively stimulated by cyclic stretch than static stretch. MGF was detected only in osteoblasts subjected to mechanical stretch,suggesting MGF was a stretch sensitive growth factor.Expression of MGF peaked earlier than that of L.IGF-1, which was similar to their regulation in muscie and suggested similar roles of MGF and L.IGF-1in bone as in muscle cells. The functions of MGF and L.IGF-1 in osteoblasts shall be established by further experimental studies.

DHT and testosterone, but not DHEA or E2, differentially modulate IGF-I, IGFBP-2, and IGFBP-3 in human prostatic stromal cells.

Science.gov (United States)

Le, Hanh; Arnold, Julia T; McFann, Kimberly K; Blackman, Marc R

2006-05-01

Prostate cancer is one of the four most common cancers in the United States, affecting one of six men. Increased serum levels of androgens and IGF-I are associated with an augmented risk of prostate cancer. Dihydrotestosterone (DHT) and testosterone (T) stimulate prostate cancer cell growth, development, and function, whereas the effects of DHT and T in prostate stromal cells, and of dehydroepiandrosterone (DHEA) in prostate cancer or stromal cells, are uncertain. We investigated the actions of DHT, T, DHEA, and estradiol (E2) on insulin-like growth factor (IGF)-I, IGF-II, IGF-I receptor (R), IGF-binding protein (IGFBP)-2, IGFBP-3, and IGFBP-5 in primary cultures of human prostatic stromal cells by assessing cell proliferation, mRNA expression, and protein secretion by MTT growth assay, quantitative real-time PCR, and ELISA, respectively. DHT and T each increased IGF-I (7-fold) and decreased IGFBP-3 (2-fold) mRNA expression and protein secretion in a dose- and time-dependent manner and increased IGFBP-2 (2-fold) mRNA in a dose- and time-dependent manner. DHEA and E2 did not significantly alter these measures. Flutamide abolished the DHT-modulated increases in IGF-I and IGFBP-2, suggesting that the influences of DHT and T on these measures were androgen receptor mediated. None of the four steroids significantly affected IGF-IR, IGF-II, or IGFBP-5 mRNA levels or stromal cell proliferation. The effects of DHT on IGF-I, IGFBP-2, and IGFBP-3 were more pronounced in stromal cultures that did not express desmin. These data suggest that DHT and T promote prostate growth partly via modulation of the stromal cell IGF axis, with potential paracrine effects on prostate epithelial cells.

Identification of imprinted genes subject to parent-of-origin specific expression in Arabidopsis thaliana seeds

LENUS (Irish Health Repository)

McKeown, Peter C

2011-08-12

Abstract Background Epigenetic regulation of gene dosage by genomic imprinting of some autosomal genes facilitates normal reproductive development in both mammals and flowering plants. While many imprinted genes have been identified and intensively studied in mammals, smaller numbers have been characterized in flowering plants, mostly in Arabidopsis thaliana. Identification of additional imprinted loci in flowering plants by genome-wide screening for parent-of-origin specific uniparental expression in seed tissues will facilitate our understanding of the origins and functions of imprinted genes in flowering plants. Results cDNA-AFLP can detect allele-specific expression that is parent-of-origin dependent for expressed genes in which restriction site polymorphisms exist in the transcripts derived from each allele. Using a genome-wide cDNA-AFLP screen surveying allele-specific expression of 4500 transcript-derived fragments, we report the identification of 52 maternally expressed genes (MEGs) displaying parent-of-origin dependent expression patterns in Arabidopsis siliques containing F1 hybrid seeds (3, 4 and 5 days after pollination). We identified these MEGs by developing a bioinformatics tool (GenFrag) which can directly determine the identities of transcript-derived fragments from (i) their size and (ii) which selective nucleotides were added to the primers used to generate them. Hence, GenFrag facilitates increased throughput for genome-wide cDNA-AFLP fragment analyses. The 52 MEGs we identified were further filtered for high expression levels in the endosperm relative to the seed coat to identify the candidate genes most likely representing novel imprinted genes expressed in the endosperm of Arabidopsis thaliana. Expression in seed tissues of the three top-ranked candidate genes, ATCDC48, PDE120 and MS5-like, was confirmed by Laser-Capture Microdissection and qRT-PCR analysis. Maternal-specific expression of these genes in Arabidopsis thaliana F1 seeds was

Identification of imprinted genes subject to parent-of-origin specific expression in Arabidopsis thaliana seeds

Directory of Open Access Journals (Sweden)

Wennblom Trevor J

2011-08-01

Full Text Available Abstract Background Epigenetic regulation of gene dosage by genomic imprinting of some autosomal genes facilitates normal reproductive development in both mammals and flowering plants. While many imprinted genes have been identified and intensively studied in mammals, smaller numbers have been characterized in flowering plants, mostly in Arabidopsis thaliana. Identification of additional imprinted loci in flowering plants by genome-wide screening for parent-of-origin specific uniparental expression in seed tissues will facilitate our understanding of the origins and functions of imprinted genes in flowering plants. Results cDNA-AFLP can detect allele-specific expression that is parent-of-origin dependent for expressed genes in which restriction site polymorphisms exist in the transcripts derived from each allele. Using a genome-wide cDNA-AFLP screen surveying allele-specific expression of 4500 transcript-derived fragments, we report the identification of 52 maternally expressed genes (MEGs displaying parent-of-origin dependent expression patterns in Arabidopsis siliques containing F1 hybrid seeds (3, 4 and 5 days after pollination. We identified these MEGs by developing a bioinformatics tool (GenFrag which can directly determine the identities of transcript-derived fragments from (i their size and (ii which selective nucleotides were added to the primers used to generate them. Hence, GenFrag facilitates increased throughput for genome-wide cDNA-AFLP fragment analyses. The 52 MEGs we identified were further filtered for high expression levels in the endosperm relative to the seed coat to identify the candidate genes most likely representing novel imprinted genes expressed in the endosperm of Arabidopsis thaliana. Expression in seed tissues of the three top-ranked candidate genes, ATCDC48, PDE120 and MS5-like, was confirmed by Laser-Capture Microdissection and qRT-PCR analysis. Maternal-specific expression of these genes in Arabidopsis thaliana F1

The ZBED6-IGF2 axis has a major effect on growth of skeletal muscle and internal organs in placental mammals

DEFF Research Database (Denmark)

Younis, Shady; Schönke, Milena; Massart, Julie

2018-01-01

expression in pig skeletal muscle. Here, we investigated the biological significance of ZBED6-IGF2 interaction in the growth of placental mammals using two mouse models, ZBED6 knock-out (Zbed6-/-) and Igf2 knock-in mice that carry the pig IGF2 mutation. These transgenic mice exhibit markedly higher serum IGF......, transcriptome analysis of the adult skeletal muscle revealed that this elevated expression of Igf2 was derived from the P1 and P2 promoters. The results revealed very similar phenotypic effects in the Zbed6 knock-out mouse and in the Igf2 knock-in mouse, showing that the effect of ZBED6 on growth of muscle...

IGF-1/IGF-1R/hsa-let-7c axis regulates the committed differentiation of stem cells from apical papilla

Science.gov (United States)

Ma, Shu; Liu, Genxia; Jin, Lin; Pang, Xiyao; Wang, Yanqiu; Wang, Zilu; Yu, Yan; Yu, Jinhua

2016-01-01

Insulin-like growth factor-1 (IGF-1) and its receptor IGF-1R play a paramount role in tooth/bone formation while hsa-let-7c actively participates in the osteogenic differentiation of mesenchymal stem cells. However, the interaction between IGF-1/IGF-1R and hsa-let-7c on the committed differentiation of stem cells from apical papilla (SCAPs) remains unclear. In this study, human SCAPs were isolated and treated with IGF-1 and hsa-let-7c over/low-expression viruses. The odonto/osteogenic differentiation of these stem cells and the involvement of mitogen-activated protein kinase (MAPK) pathway were subsequently investigated. Alizarin red staining showed that hsa-let-7c low-expression can significantly promote the mineralization of IGF-1 treated SCAPs, while hsa-let-7c over-expression can decrease the calcium deposition of IGF-1 treated SCAPs. Western blot assay and real-time reverse transcription polymerase chain reaction further demonstrated that the expression of odonto/osteogenic markers (ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN, COL-I/COL-I, DSPP/DSP, and DMP-1/DMP-1) in IGF-1 treated SCAPs were significantly upregulated in Let-7c-low group. On the contrary, hsa-let-7c over-expression could downregulate the expression of these odonto/osteogenic markers. Moreover, western blot assay showed that the JNK and p38 MAPK signaling pathways were activated in Let-7c-low SCAPs but inhibited in Let-7c-over SCAPs. Together, the IGF-1/IGF-1R/hsa-let-7c axis can control the odonto/osteogenic differentiation of IGF-1-treated SCAPs via the regulation of JNK and p38 MAPK signaling pathways. PMID:27833148

Maternal insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and IGF BP-3 and the hypertensive disorders of pregnancy.

LENUS (Irish Health Repository)

Cooley, Sharon M

2010-07-01

To investigate the relationship between levels of insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and insulin-like growth factor binding protein 3 (IGFBP-3) in antenatal maternal serum and gestational hypertension and pre-eclampsia (PET).

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

International Nuclear Information System (INIS)

Liu, Ping; Kong, Feng; Wang, Jue; Lu, Qinghua; Xu, Haijia; Qi, Tonggang; Meng, Juan

2015-01-01

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS expression

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

Energy Technology Data Exchange (ETDEWEB)

Liu, Ping, E-mail: lping@sdu.edu.cn [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China); Kong, Feng; Wang, Jue [Central Laboratory, The Second Hospital of Shandong University, Shandong, Jinan 250033 (China); Lu, Qinghua [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China); Xu, Haijia [Department of Cardiology, Wendeng Central Hospital of Weihai City, Shandong, Weihai 264400 (China); Qi, Tonggang [Central Laboratory, The Second Hospital of Shandong University, Shandong, Jinan 250033 (China); Meng, Juan [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China)

2015-02-01

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS expression

Mechanisms Underlying Testicular Damage and Dysfunction in Mice With Partial IGF-1 Deficiency and the Effectiveness of IGF-1 Replacement Therapy.

Science.gov (United States)

Castilla-Cortázar, Inma; Gago, Alberto; Muñoz, Úrsula; Ávila-Gallego, Elena; Guerra-Menéndez, Lucía; Sádaba, María Cruz; García-Magariño, Mariano; Olleros Santos-Ruiz, María; Aguirre, G A; Puche, Juan Enrique

2015-12-01

To determine whether insulin-like growth factor (IGF-1) deficiency can cause testicular damage and to examine changes of the testicular morphology and testicular function-related gene expression caused by IGF-1 deficiency. Therefore, this study aims to determine the benefits of low doses of IGF-1 and to explore the mechanisms underlying the IGF-1 replacement therapy. A murine model of IGF-1 deficiency was used to avoid any factor that could contribute to testicular damage. Testicular weight, score of histopathological damage, and gene expressions were studied in 3 experimental groups of mice: controls (wild-type Igf1(+/+)), heterozygous Igf1(+/-) with partial IGF-1 deficiency, and heterozygous Igf1(+/-) treated with IGF-1. Results show that the partial IGF-1 deficiency induced testicular damage and altered expression of genes involved in IGF-1 and growth hormone signaling and regulation, testicular hormonal function, extracellular matrix establishment and its regulation, angiogenesis, fibrogenesis, inflammation, and cytoprotection. In addition, proteins involved in tight junction expression were found to be reduced. However, low doses of IGF-1 restored the testicular damage and most of these parameters. IGF-1 deficiency caused the damage of the blood-testis barrier and testicular structure and induced the abnormal testicular function-related gene expressions. However, low doses of IGF-1 constitute an effective replacement therapy that restores the described testicular damage. Data herein show that (1) cytoprotective activities of IGF-1 seem to be mediated by heat shock proteins and that (2) connective tissue growth factor could play a relevant role together with IGF-1 in the extracellular matrix establishment. Copyright © 2015 Elsevier Inc. All rights reserved.

MMP-2 participates in the sclera of guinea pig with form-deprivation myopia via IGF-1/STAT3 pathway.

Science.gov (United States)

Liu, Y-X; Sun, Y

2018-05-01

To investigate the expression changes of MMP-2 (matrix metalloproteinases-2) mediated by IGF-1 (insulin-like growth factors-1) STAT3 (signal transducer and activator of transcription 3) pathway in the sclera of the form-deprivation myopia guinea pigs. Twenty-four three-week-old guinea pigs were randomly divided into 4 groups: group A (Control), B, C and D. Guinea pigs in group A were sacrificed after 21 days without any special treatment. Guinea pigs in group B were sacrificed 7 days after receiving stitch in the right eye. Guinea pigs in group C were sacrificed 14 days after receiving stitch in the right eye. Guinea pigs in group D were sacrificed 21 days after receiving stitch in the right eye. Eyeball refraction and axial length of guinea pigs were measured before sacrifice. Eyeballs of guinea pigs were enucleated after sacrifice. The expressions of IGF-1, STAT3 and MMP-2 in scleral tissue were detected by Western blot. Axial length extension and myopia appeared in the right eye of guinea pigs in group B. The expressions of IGF-1, STAT3 and MMP-2 in the sclera significantly increased after 7 days of occlusion compared with that in control group A (pIGF-1, STAT3 and MMP-2 in sclera significantly increased compared with that in group A (pIGF-1, STAT3 and MMP-2 in scleral significantly upregulated 21 days after occlusion (pIGF-1 in sclera were positively correlated (r = 0.962, pIGF-1, STAT3 and MMP-2 in the sclera and myopia of guinea pigs. The expressions of IGF-1, STAT3 and MMP-2 increased progressively over the time of deprivation. Additionally, overexpression of MMP-2 mediated by IGF-1/STAT3 pathway in sclera might promote the formation of myopia.

Role of IGF-1/IGF-1R in regulation of invasion in DU145 prostate cancer cells

Directory of Open Access Journals (Sweden)

Setya Hemani

2008-07-01

Full Text Available Abstract Background Prostate cancer progression to androgen independence is the primary cause of mortality by this tumor type. The IGF-1/IGF-1R axis is well known to contribute to prostate cancer initiation, but its contribution to invasiveness and the downstream signalling mechanisms that are involved are unclear at present. Results We examined the invasive response of androgen independent DU145 prostate carcinoma cells to IGF-1 stimulation using Matrigel assays. We then examined the signaling mechanisms and protease activities that are associated with this response. IGF-1 significantly increased the invasive capacity of DU145 cells in vitro, and this increase was inhibited by blocking IGF-1R. We further demonstrated that specific inhibitors of the MAPK and PI3-K pathways decrease IGF-1-mediated invasion. To determine potential molecular mechanisms for this change in invasive capacity, we examined changes in expression and activity of matrix metalloproteinases. We observed that IGF-1 increases the enzymatic activity of MMP-2 and MMP-9 in DU145 cells. These changes in activity are due to differences in expression in the case of MMP-9 but not in the case of MMP-2. This observation is corroborated by the fact that correlated changes of expression in a regulator of MMP-2, TIMP-2, were also seen. Conclusion This work identifies a specific effect of IGF-1 on the invasive capacity of DU145 prostate cancer cells, and furthermore delineates mechanisms that contribute to this effect.

IGF-1 receptor and IGF binding protein-3 might predict prognosis of patients with resectable pancreatic cancer

International Nuclear Information System (INIS)

Hirakawa, Toshiki; Yashiro, Masakazu; Murata, Akihiro; Hirata, Keiichiro; Kimura, Kenjiro; Amano, Ryosuke; Yamada, Nobuya; Nakata, Bunzo; Hirakawa, Kosei

2013-01-01

The present study aimed to elucidate the clinicopathologic role of insulin-like growth factor-1 receptor (IGF1R) and IGF binding protein-3 (IGFBP3) in patients with pancreatic cancer. The function of IGFBP3 is controversial, because both inhibition and facilitation of the action of IGF as well as IGF-independent effects have been reported. In this study, IGF1R and IGFBP3 expression was examined, and their potential roles as prognostic markers in patients with pancreatic cancer were evaluated. Clinicopathological features of 122 patients with curatively resected pancreatic cancer were retrospectively reviewed, and expression of IGF1R and IGFBP3 was immunohistochemically analyzed. Expression of IGF1R and IGFBP3 was observed in 50 (41.0%) and 37 (30.3%) patients, respectively. IGF1R expression was significantly associated with histological grade (p = 0.037). IGFBP3 expression had a significant association with tumor location (p = 0.023), and a significant inverse association with venous invasion (p = 0.037). Tumors with IGF1R-positive and IGFBP3-negative expression (n = 32) were significantly frequently Stage II and III (p = 0.011). The prognosis for IGF1R positive patients was significantly poorer than that for IGF1R negative patients (p = 0.0181). IGFBP3 protein expression did not correlate significantly with patient survival. The subset of patients with both positive IGF1R and negative IGFBP3 had worse overall survival (8.8 months versus 12.6 months, respectively, p < 0.001). IGF1R signaling might be associated with tumor aggressiveness, and IGFBP3 might show antiproliferative effects in pancreatic cancer. Both high IGF1R expression and low IGFBP3 expression represent useful prognostic markers for patients with curatively resected pancreatic cancer

Expression of IGF-I and Protein Degradation Markers During Hindlimb Unloading and Growth Hormone Administration in Rats

Science.gov (United States)

Leinsoo, T. A.; Turtikova, O. V.; Shenkman, B. S.

2013-02-01

It is known that hindlimb unloading or spaceflight produce atrophy and a number of phenotypic alterations in skeletal muscles. Many of these processes are triggered by the axis growth hormone/insulin-like growth factor I. However growth hormone (GH) and insulin-like growth factor I (IGF-I) expression relationship in rodent models of gravitational unloading is weakly investigated. We supposed the IGF-I is involved in regulation of protein turnover. In this study we examined the IGF-I expression by RT-PCR assay in the rat soleus, tibialis anterior and liver after 3 day of hindlimb suspension with growth hormone administration. Simultaneously were studied expression levels of MuRF-1 and MAFbx/atrogin as a key markers of intracellular proteolysis. We demonstrated that GH administration did not prevent IGF-I expression decreasing under the conditions of simulated weightlessness. It was concluded there are separate mechanisms of action of GH and IGF-I on protein metabolism in skeletal muscles. Gravitational unloading activate proteolysis independently of growth hormone activity.

Platycodon grandiflorum (PG) reverses angiotensin II-induced apoptosis by repressing IGF-IIR expression.

Science.gov (United States)

Lin, Yuan-Chuan; Lin, Chih-Hsueh; Yao, Hsien-Tsung; Kuo, Wei-Wen; Shen, Chia-Yao; Yeh, Yu-Lan; Ho, Tsung-Jung; Padma, V Vijaya; Lin, Yu-Chen; Huang, Chih-Yang; Huang, Chih-Yang

2017-06-09

Platycodon grandiflorum (PG) is a Chinese medical plant used for decades as a traditional prescription to eliminate phlegm, relieve cough, reduce inflammation and lower blood pressure. PG also has a significant effect on the cardiovascular systems. The aqueous extract of Platycodon grandiflorum (JACQ.) A. DC. root was screened for inhibiting Ang II-induced IGF-IIR activation and apoptosis pathway in H9c2 cardiomyocytes. The effects were also studied in spontaneously hypertensive rats (five groups, n=5) using low and high doses of PG for 50 days. The Ang II-induced IGF-IIR activation was analyzed by luciferase reporter, RT-PCR, western blot and surface IGF-IIR expression assay. Furthermore, the major active constituent of PG was carried out by high performance liquid chromatography-mass spectrometry (HPLC-MS). Our results indicate that a crude extract of PG significantly suppresses the Ang II-induced IGF-IIR signaling pathway to prevent cardiomyocyte apoptosis. PG extract inhibits Ang II-mediated JNK activation and SIRT1 degradation to reduce IGF-IIR activity. Moreover, PG maintains SIRT1 stability to enhance HSF1-mediated IGF-IIR suppression, which prevents cardiomyocyte apoptosis. In animal models, the administration of PG markedly reduced this apoptotic pathway in the heart of SHRs. Taken together, PG may be considered as an effective treatment for cardiac diseases in hypertensive patients. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Serum from Chronic Hepatitis B Patients Promotes Growth and Proliferation via the IGF-II/IGF-IR/MEK/ERK Signaling Pathway in Hepatocellular Carcinoma Cells.

Science.gov (United States)

Ji, Yuanyuan; Wang, Zhidong; Chen, Haiyan; Zhang, Lei; Zhuo, Fei; Yang, Qingqing

2018-05-09

Chronic hepatitis B virus (HBV) infection (CHB) plays a central role in the etiology of hepatocellular carcinoma (HCC). Emerging evidence implicates insulin-like growth factor (IGF)-II as a major risk factor for the growth and development of HCC. However, the relationship between HBV infection and IGF-II functions remains to be elucidated. Levels of circulating IGF-II and IGF-I receptor (IGF-IR) in healthy donors (HDs) and CHB patients were tested by ELISA. Human HCC cell lines (HepG-2, SMMC-7721, MHCC97-H) were incubated with serum from HDs and CHB patients at various concentrations for 24, 48, and 72 h. MTT and plate colony formation assays, BrdU ELISA, ELISA, small-interfering RNA (siRNA) transfection, quantitative real-time PCR, and western blot were applied to assess the functional and molecular mechanisms in HCC cell lines. Serum levels of IGF-II and IGF-IR were significantly higher in CHB patients than in HDs. Additionally, serum from CHB patients directly induced cell growth, proliferation, IGF-II secretion, and HDGF-related protein-2 (HRP-2) and nuclear protein 1 (NUPR1) mRNA and protein expression in HCC cells. Moreover, serum from CHB patients increased IGF-II-induced cell growth, proliferation, and HRP-2 and NUPR1 mRNA and protein expression in HCC cells. Blockade of IGF-IR clearly inhibited the above effects. Most importantly, interference with IGF-II function markedly repressed the cell proliferation and HRP-2 and NUPR1 mRNA and protein expression induced by serum from CHB patients. Furthermore, serum from CHB patients induced ERK phosphorylation via IGF-IR, with the MEK inhibitor PD98059 significantly decreasing CHB patient serum-induced IGF-II secretion, cell proliferation, and HRP-2 and NUPR1 mRNA and protein expression. Serum from CHB patients increases cell growth and proliferation and enhances HRP-2 and NUPR1 expression in HCC cells via the IGF-II/IGF-IR/MEK/ERK signaling pathway. These findings help to explain the molecular mechanisms

Structural analysis of the interaction of IGF I with the IGF types 1 and 2 and insulin receptors

International Nuclear Information System (INIS)

Cascieri, M.A.; Chicchi, G.G.; Hayes, N.S.; Green, B.G.; Applebaum, J.A.; Bayne, M.L.

1987-01-01

A synthetic gene for human IGF I has been synthesized which directs the synthesis and secretion of fully active human IGF I (rIGF I) from yeast. rIGF I inhibits binding of 125 I-IGF I to type 1 IGF receptors from human placenta (IGF-R1, IC50 = 4 nM), binding of 125 I-insulin to insulin receptors (IR, IC50 = 881 nM), binding of 125 I-MSA to type 2 IGF receptors from rat liver (IGF-R2, IC50 = 80 nM), and binding of 125 I-IGF I to crude human serum binding protein (hBP, IC50 = 0.42 nM). rIGF I is equipotent to human IGF I in stimulating glucose transport in murine BC3H1 cells and in stimulating DNA synthesis in rat A10 cells. Site directed mutagenesis of the synthetic gene is being used to characterize the structural requirements for binding to these receptors. IGF I (FFY) B(23-25) is equipotent to rIGF I at the IGF-R1 (6.9 nM), the IGF-R2 (36 nM), and the IR (841 nM) and is less potent at the hBP (1.7 nM). In contrast, IGF I(SFY) B(23-25) is 20-fold less potent than rIGF I at the IGF-R1 and is 10-fold less potent than rIGF I at hBP. This peptide is greater than 10-fold less active at the IGF-R2 and the IR. This peptide is a full agonist in the cell assays but 20-50 fold less potent than rIGF I. These data are consistent with the hypothesis that the F to S change destabilizes the tertiary structure of IGF I

The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human renal cell carcinoma cell growth.

Science.gov (United States)

Su, Ying; Zhao, An; Cheng, Guoping; Xu, Jingjing; Ji, Enming; Sun, Wenyong

2017-07-04

Renal cell carcinoma (RCC) is the highest mortality rate of the genitourinary cancers, and the treatment options are very limited. Thus, identification of molecular mechanisms underlying RCC tumorigenesis, is critical for identifying biomarkers for RCC diagnosis and prognosis. To validate whether the IGF-I/JAK2-STAT3/miR-21 signaling pathway is associated with human RCC cell growth. qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels, respectively. The MTT assay was performed to determine cell survival rate. The Annexin V-FITC/PI apoptosis detection kit was used to detect cell apoptosis. We employed RCC tissues and cell lines (A498; ACHN; Caki-1; Caki-2 and 786-O) in the study. IGF-I, and its inhibitor (NT-157) were administrated to detect the effects of IGF-I on the expression of miR-21 and p-JAK2. JAK2 inhibitor (AG490), and si-STAT3 were used to detect the effects of JAK2/STAT3 signaling pathway on the expression of miR-21. In our study, we firstly showed that the expression levels of IGF-I and miR-21 were up-regulated in RCC tissues and cell lines. After exogenous IGF-I treatment, the expression levels of miR-21, p-IGF-IR and p-JAK2 were significantly increased, whereas NT-157 treatment showed the reversed results. Further study indicated that JAK2 inhibitor or si-STAT3 significantly reversed the IGF-I-induced miR-21 expression level. Finally, we found that IGF-I treatment significantly prompted human RCC cell survival and inhibited cell apoptosis, and NT-157 treatment showed the reversed results. The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human RCC cell growth.

[Neurobiology of imprinting].

Science.gov (United States)

Ohki-Hamazaki, Hiroko

2012-06-01

Imprinting is an example of learning and memory acquisition in infancy. In the case of precocial birds, such as geese, ducks, and chickens, the baby birds learn the characteristics of the first moving object that they see within a critical period, and they imprint on it and follow it around. We analyzed the neural basis of this behavior in order to understand the neural mechanism of learning and memory in infancy. Information pertaining to a visual imprinting stimulus is recognized and processed in the visual Wulst, a region that corresponds to the mammalian visual cortex. It is then transmitted to the posterior region of the telencephalon, followed by the core region of the hyperpallium densocellulare (HDCo), periventricular region of the hyperpallium densocellulare (HDPe), and finally, the intermediate medial mesopallium (IMM), a region similar to the mammalian association cortex. Memory is stored in the IMM. After imprint training, plastic changes are observed in the visual Wulst as well as in the neurons of this circuit. HDCo cells, located at the center of this circuit, express N-methyl-D-aspartate (NMDA) receptors containing the NMDA receptor (NR) 2B subunit; the expression of this receptor increased after the imprint training. Inhibition of this receptor in the cells of the HDCo region leads to failure of imprinting and inactivation of this circuit. Thus, NMDA receptors bearing the NR2B subunit play a critical role in plastic changes in this circuit and in induction of imprinting.

Obesity alters gene expression for GH/IGF-I axis in mouse mammary fat pads: differential role of cortistatin and somatostatin.

Directory of Open Access Journals (Sweden)

Alicia Villa-Osaba

Full Text Available Locally produced growth hormone (GH and IGF-I are key factors in the regulation of mammary gland (MG development and may be important in breast cancer development/progression. Somatostatin (SST and cortistatin (CORT regulate GH/IGF-I axis at various levels, but their role in regulating GH/IGF-I in MGs remains unknown. Since obesity alters the expression of these systems in different tissues and is associated to MG (patho physiology, we sought to investigate the role of SST/CORT in regulating GH/IGF-I system in the MGs of lean and obese mice. Therefore, we analyzed GH/IGF-I as well as SST/CORT and ghrelin systems expression in the mammary fat pads (MFPs of SST- or CORT-knockout (KO mice and their respective littermate-controls fed a low-fat (LF or a high-fat (HF diet for 16 wks. Our results demonstrate that the majority of the components of GH/IGF-I, SST/CORT and ghrelin systems are locally expressed in mouse MFP. Expression of elements of the GH/IGF-I axis was significantly increased in MFPs of HF-fed control mice while lack of endogenous SST partially suppressed, and lack of CORT completely blunted, the up-regulation observed in obese WT-controls. Since SST/CORT are known to exert an inhibitory role on the GH/IGFI axis, the increase in SST/CORT-receptor sst2 expression in MFPs of HF-fed CORT- and SST-KOs together with an elevation on circulating SST in CORT-KOs could explain the differences observed. These results offer new information on the factors (GH/IGF-I axis involved in the endocrine/metabolic dysregulation of MFPs in obesity, and suggest that CORT is not a mere SST sibling in regulating MG physiology.

IGF-1 induces the epithelial-mesenchymal transition via Stat5 in hepatocellular carcinoma.

Science.gov (United States)

Zhao, Chuanzong; Wang, Qian; Wang, Ben; Sun, Qi; He, Zhaobin; Hong, Jianguo; Kuehn, Florian; Liu, Enyu; Zhang, Zongli

2017-12-19

It has been reported that the epithelial-mesenchymal transition (EMT) plays an important role in hepatocellular carcinoma (HCC). However, the relationship between the insulin-like growth factor-1 (IGF-1) and EMT of HCC was not fully elucidated. In the present work, we found that the expression of N-cadherin, Vimentin, Snail1, Snail2, and Twist1 was positively associated with IGF-1R expression, while E-cadherin expression was negatively associated with IGF-1 expression in human HCC samples. Furthermore, we observed that IGF-1 up-regulated the expression of N-cadherin, Vimentin, Snail1, Snail2 and Twist1, and down-regulated the expression of E-cadherin. In addition, Stat5 was induced in IGF-1-treated HepG2 and Hep3B cells, and Stat5 inhibition or siRNA significantly affected IGF-1-induced EMT in HepG2 and Hep3B cells. In conclusion, IGF-1 induces EMT of HCC via Stat5 signaling pathway. Thus, IGF-1/Stat5 can be recommended as a potential and novel therapeutic strategy for HCC patients.

Parental genome dosage imbalance deregulates imprinting in Arabidopsis.

Directory of Open Access Journals (Sweden)

Pauline E Jullien

2010-03-01

Full Text Available In mammals and in plants, parental genome dosage imbalance deregulates embryo growth and might be involved in reproductive isolation between emerging new species. Increased dosage of maternal genomes represses growth while an increased dosage of paternal genomes has the opposite effect. These observations led to the discovery of imprinted genes, which are expressed by a single parental allele. It was further proposed in the frame of the parental conflict theory that parental genome imbalances are directly mirrored by antagonistic regulations of imprinted genes encoding maternal growth inhibitors and paternal growth enhancers. However these hypotheses were never tested directly. Here, we investigated the effect of parental genome imbalance on the expression of Arabidopsis imprinted genes FERTILIZATION INDEPENDENT SEED2 (FIS2 and FLOWERING WAGENINGEN (FWA controlled by DNA methylation, and MEDEA (MEA and PHERES1 (PHE1 controlled by histone methylation. Genome dosage imbalance deregulated the expression of FIS2 and PHE1 in an antagonistic manner. In addition increased dosage of inactive alleles caused a loss of imprinting of FIS2 and MEA. Although FIS2 controls histone methylation, which represses MEA and PHE1 expression, the changes of PHE1 and MEA expression could not be fully accounted for by the corresponding fluctuations of FIS2 expression. Our results show that parental genome dosage imbalance deregulates imprinting using mechanisms, which are independent from known regulators of imprinting. The complexity of the network of regulations between expressed and silenced alleles of imprinted genes activated in response to parental dosage imbalance does not support simple models derived from the parental conflict hypothesis.

MeCP2 silencing of LncRNA H19 controls hepatic stellate cell proliferation by targeting IGF1R

International Nuclear Information System (INIS)

Yang, Jing-Jing; Liu, Li-Ping; Tao, Hui; Hu, Wei; Shi, Peng; Deng, Zi-Yu; Li, Jun

2016-01-01

Highlights: • H19 plays a key role in HSCs proliferation and fibrosis. • MeCP2/H19 axis involvement in HSCs activation and fibrosis. • MeCP2 negative controls H19 expression in activated HSCs. • Identification of IGF1R as new target of H19 in HSC. - Abstract: Methyl-CpG-binding protein 2 (MeCP2) plays a key role in liver fibrosis. However, the potential mechanism of MeCP2 in liver fibrosis remains unclear. Early reports suggest that LncRNA H19 is important epigenetic regulator with critical roles in cell proliferation, but its role in hepatic fibrosis remains elusive. Sprague-Dawley rats liver fibrosis was generated by 12-weeks treatment with CCl 4 intraperitoneal injection. HSC-T6 cells were used in vitro study. The expression levels of MeCP2, H19, IGF1R, α-SMA, and Col1A1 were estimated by Western blotting, qRT-PCR and Immunohistochemistry. HSC-T6 cells were transfected with MeCP2-siRNA, pEGF-C1-MeCP2, pEX-3-H19, and H19-siRNA. Finally, cell proliferation ability was assessed by the MTT assay. Here, we found that H19 was significantly down-regulated in HSCs and fibrosis tissues, and an opposite pattern is observed for MeCP2 and IGF1R. Silencing of MeCP2 blocked HSCs proliferation. Knockdown of MeCP2 elevated H19 expression in activated HSCs, and over-expression of MeCP2 inhibited H19 expression in activated HSCs. Moreover, we investigated the effect of H19 on IGF1R expression. Overexpression of H19 in HSCs repressed the expression of IGF1R, and an opposite pattern is observed for H19 silenced. In addition, we reported that overexpression of H19 inhibited the TGF-β1-induced proliferation of HSCs. Furthermore, MeCP2 negative regulation of H19 by targeting the protein IGF1R. Taken together, these results demonstrated that MeCP2 silencing of H19 can alter the IGF1R overexpression, thus contributing to HSCs proliferation. These data could suggest the development of combination therapies that target the MeCP2.

Impact of IGF-1, IGF-1R, and IGFBP-3 promoter methylation on the risk and prognosis of esophageal carcinoma.

Science.gov (United States)

Ye, Peng; Qu, Chang-Fa; Hu, Xue-Lin

2016-05-01

The aim of this study is to investigate IGF-1, IGF-1R, and IGFBP-3 methylations in esophageal carcinoma (EC) patients and their relationship with the development and prognosis of EC. This study population consisted of 264 patients (case group) whom EC radical resection was performed and 283 healthy individuals (control group). Methylation-specific PCR (MSP) detected the methylation status of IGF-1, IGF-1R, and IGFBP-3 in the peripheral blood in both groups. The expressions of IGF-1, IGF-1R, and IGFBP-3 in EC and adjacent normal tissues were detected by immunohistochemistry (IHC). The methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 in the case group were higher than those in the control group (all P IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 IGF-1 among patients of different clinicopathological features (all P IGF-1 and IGF-1R in EC were significantly higher than those in adjacent normal tissues (both P IGF-1 and IGF1R gene promoter methylation was positively correlated with the positive expressions of IGF-1 (r = 0.139, P = 0.024) and IGF-1R (r = 0.135, P = 0.028), while the IGFBP3 methylation was negatively correlated with the positive expression of IGFBP3 (r = -0.133, P = 0.031). The positive expressions of IGF-1, IGF-1R, and IGFBP-3 were related to different clinicopathological features (all P IGF-1, IGF-1R, and IGF-1 + IGF1R + IGFBP3 ; expressions of IGF-1 and IGF-1R protein; infiltration depth; and lymph node metastasis (LNM) were independent factors of EC prognosis. Our study demonstrated that methylation of IGF-1, IGF1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 was closely linked with the occurrence of EC and patients' clinicopathological features. Besides, the methylation status of the target genes and the expressions of IGF-1 and IGF-1R protein were independent factors of EC prognosis, which could provide a direction for the prognosis and treatment of EC.

Stress-altered synaptic plasticity and DAMP signaling in the hippocampus-PFC axis; elucidating the significance of IGF-1/IGF-1R/CaMKIIα expression in neural changes associated with a prolonged exposure therapy.

Science.gov (United States)

Ogundele, Olalekan M; Ebenezer, Philip J; Lee, Charles C; Francis, Joseph

2017-06-14

Traumatic stress patients showed significant improvement in behavior after a prolonged exposure to an unrelated stimulus. This treatment method attempts to promote extinction of the fear memory associated with the initial traumatic experience. However, the subsequent prolonged exposure to such stimulus creates an additional layer of neural stress. Although the mechanism remains unclear, prolonged exposure therapy (PET) likely involves changes in synaptic plasticity, neurotransmitter function and inflammation; especially in parts of the brain concerned with the formation and retrieval of fear memory (Hippocampus and Prefrontal Cortex: PFC). Since certain synaptic proteins are also involved in danger-associated molecular pattern signaling (DAMP), we identified the significance of IGF-1/IGF-1R/CaMKIIα expression as a potential link between the concurrent progression of synaptic and inflammatory changes in stress. Thus, a comparison between IGF-1/IGF-1R/CaMKIIα, synaptic and DAMP proteins in stress and PET may highlight the significance of PET on synaptic morphology and neuronal inflammatory response. In behaviorally characterized Sprague-Dawley rats, there was a significant decline in neural IGF-1 (pIGF-1R expression. These animals showed a significant loss of presynaptic markers (synaptophysin; pIGF-1 (pIGF-1R was recorded in the Stress-PET group (pIGF-1/IGF-1R, an increase in activated hippocampal and cortical microglia was seen in stress (pIGF1/IGF-1R/CaMKIIα. Firstly, we showed a direct relationship between IGF-1/IGF-1R expression, presynaptic function (synaptophysin) and neurotransmitter activity in stress and PET. Secondly, we identified the possible role of CaMKIIα in post-synaptic function and regulation of small ion conductance channels. Lastly, we highlighted some of the possible links between IGF1/IGF-1R/CaMKIIα, the expression of DAMP proteins, Microglia activation, and its implication on synaptic plasticity during stress and PET. Copyright © 2017

Characterization of insulin-like-growth factor II (IGF II mRNA positive hepatic altered foci and IGF II expression in hepatocellular carcinoma during diethylnitrosamine-induced hepatocarcinogenesis in rats

Directory of Open Access Journals (Sweden)

Mukherjee Biswajit

2005-08-01

Full Text Available Abstract Background Insulin-like-growth factor II (IGF II has been implicated in the pathogenesis of neoplasm of different tissues, including liver of rats and men. This growth factor is believed to exert its effect during cellular proliferation. During the process of development of hepatocellular carcinoma (HCC, different hepatic altered foci appear. They are believed to be the putative precursors of HCC in rats and in men. Thus, to study the role of the gene in a defined model of hepatocarcinogenesis was the target to elucidate its role in various cancer phenotypes during the entire development stage of cancer, right from earlier preneoplastic lesions to HCC Methods Antisense in situ hybridization technique was used here to characterize the type(s of foci in which IGF II mRNA had expressed during the development of hepatocarcinogenesis-induced by diethylnitrosamine and promoted by phenobarbital in rats. Various focal lesions have been categorized depending on the stages and sizes along with IGF II expression patterns in them. Immunohistochemical detection for proliferating cell nuclear antigen (PCNA was made to detect the role of the gene in preneoplastic and neoplastic cellular proliferation. Results IGF II expression was located in the glycogen-storage acidophilic cell foci maximally followed by mixed cell lesions and the least in basophilic lesions. The expression of IGF II was found to be predominant in the HCC. The expression of gene was also located at the peripheral cells of spongiosis hepatis which are believed to be the precursor of ito cell carcinoma. It was noted that there is a direct correlation between IGF II expression and Immunohistochemical detection for PCNA. Conclusion It may be concluded that IGF II gene expression plays an important role during the development of neoplasia and the gene expresses in the sequence of events leading from glycogen-rich-acidophilic lesions to glycogen poor basophilic lesions to HCC with an

Regulation of dendritic cell function by insulin/IGF-1/PI3K/Akt signaling through klotho expression.

Science.gov (United States)

Xuan, Nguyen Thi; Hoang, Nguyen Huy; Nhung, Vu Phuong; Duong, Nguyen Thuy; Ha, Nguyen Hai; Hai, Nong Van

2017-06-01

Insulin or insulin-like growth factor 1 (IGF-1) promotes the activation of phosphoinositide 3 kinase (PI3K)/Akt signaling in immune cells including dendritic cells (DCs), the most potent professional antigen-presenting cells for naive T cells. Klotho, an anti-aging protein, participates in the regulation of the PI3K/Akt signaling, thus the Ca 2+ -dependent migration is reduced in klotho-deficient DCs. The present study explored the effects of insulin/IGF-1 on DC function through klotho expression. To this end, the mouse bone marrow cells were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs). Cells were treated with insulin or IGF-1 and followed by stimulating with lipopolysaccharides (LPS). Tumor necrosis factor (TNF)-α formation was examined by enzyme-linked immunosorbent assay (ELISA). Phagocytosis was analyzed by FITC-dextran uptake assay. The expression of klotho was determined by quantitative PCR, immunoprecipitation and western blotting. As a result, treatment of the cells with insulin/IGF-1 resulted in reducing the klotho expression as well as LPS-stimulated TNF-α release and increasing the FITC-dextran uptake but unaltering reactive oxygen species (ROS) production in BMDCs. The effects were abolished by using pharmacological inhibition of PI3K/Akt with LY294002 and paralleled by transfecting DCs with klotho siRNA. In conclusion, the regulation of klotho sensitive DC function by IGF-1 or insulin is mediated through PI3K/Akt signaling pathway in BMDCs.

Dietary protein-induced hepatic IGF-1 secretion mediated by PPARγ activation.

Science.gov (United States)

Wan, Xiaojuan; Wang, Songbo; Xu, Jingren; Zhuang, Lu; Xing, Kongping; Zhang, Mengyuan; Zhu, Xiaotong; Wang, Lina; Gao, Ping; Xi, Qianyun; Sun, Jiajie; Zhang, Yongliang; Li, Tiejun; Shu, Gang; Jiang, Qingyan

2017-01-01

Dietary protein or amino acid (AA) is a crucial nutritional factor to regulate hepatic insulin-like growth factor-1 (IGF-1) expression and secretion. However, the underlying intracellular mechanism by which dietary protein or AA induces IGF-1 expression remains unknown. We compared the IGF-1 gene expression and plasma IGF-1 level of pigs fed with normal crude protein (CP, 20%) and low-protein levels (LP, 14%). RNA sequencing (RNA-seq) was performed to detect transcript expression in the liver in response to dietary protein. The results showed that serum concentrations and mRNA levels of IGF-1 in the liver were higher in the CP group than in the LP group. RNA-seq analysis identified a total of 1319 differentially expressed transcripts (667 upregulated and 652 downregulated), among which the terms "oxidative phosphorylation", "ribosome", "gap junction", "PPAR signaling pathway", and "focal adhesion" were enriched. In addition, the porcine primary hepatocyte and HepG2 cell models also demonstrated that the mRNA and protein levels of IGF-1 and PPARγ increased with the increasing AA concentration in the culture. The PPARγ activator troglitazone increased IGF-1 gene expression and secretion in a dose dependent manner. Furthermore, inhibition of PPARγ effectively reversed the effects of the high AA concentration on the mRNA expression of IGF-1 and IGFBP-1 in HepG2 cells. Moreover, the protein levels of IGF-1 and PPARγ, as well as the phosphorylation of mTOR, significantly increased in HepG2 cells under high AA concentrations. mTOR phosphorylation can be decreased by the mTOR antagonist, rapamycin. The immunoprecipitation results also showed that high AA concentrations significantly increased the interaction of mTOR and PPARγ. In summary, PPARγ plays an important role in the regulation of IGF-1 secretion and gene expression in response to dietary protein.

Intrauterine growth restriction and differential patterns of hepatic growth and expression of IGF1, PCK2, and HSDL1 mRNA in the sheep fetus in late gestation.

Science.gov (United States)

Gentili, Sheridan; Morrison, Janna L; McMillen, I Caroline

2009-06-01

Fetal adaptations to periods of substrate deprivation can result in the programming of glucose intolerance, insulin resistance, and metabolic dysfunction in later life. Placental insufficiency can be associated with either sparing or sacrifice of fetal liver growth, and these different responses may have different metabolic consequences. It is unclear what intrahepatic mechanisms determine the differential responses of the fetal liver to substrate restriction. We investigated the effects of placental restriction (PR) on liver growth and the hepatic expression of SLC2A1, IGF1, IGF2, IGF1R, IGF2R, PPARGC1A, PPARA, PRKAA1, PRKAA2, PCK2, and HSDL1 mRNA in fetal sheep at 140-145 days of gestation. A mean gestational arterial partial pressure of oxygen less than 17 mmHg was defined as hypoxic, and a relative liver of weight more than 2 SD below the mean liver weight of controls was defined as reduced liver growth. Fetuses therefore were defined as control-normoxic (C-N; n = 9), PR-normoxic (PR-N; n = 7), PR-hypoxic (PR-H; n = 8), or PR-hypoxic reduced liver growth (PR-H RLG; n = 4). Hepatic SLC2A1 mRNA expression was highest (P fetal substrate restriction may exist that protect the liver from decreased growth and, potentially, from a decreased responsiveness to the actions of insulin in postnatal life.

Imprinting disorders

DEFF Research Database (Denmark)

Eggermann, Thomas; Perez de Nanclares, Guiomar; Maher, Eamonn R

2015-01-01

Congenital imprinting disorders (IDs) are characterised by molecular changes affecting imprinted chromosomal regions and genes, i.e. genes that are expressed in a parent-of-origin specific manner. Recent years have seen a great expansion in the range of alterations in regulation, dosage or DNA...... sequence shown to disturb imprinted gene expression, and the correspondingly broad range of resultant clinical syndromes. At the same time, however, it has become clear that this diversity of IDs has common underlying principles, not only in shared molecular mechanisms, but also in interrelated clinical...

Insulin-Like Growth Factor (IGF System in Liver Diseases

Directory of Open Access Journals (Sweden)

Agnieszka Adamek

2018-04-01

Full Text Available Hepatocyte differentiation, proliferation, and apoptosis are affected by growth factors produced in liver. Insulin-like growth factor 1 and 2 (IGF1 and IGF2 act in response to growth hormone (GH. Other IGF family components include at least six binding proteins (IGFBP1 to 6, manifested by both IGFs develop due to interaction through the type 1 receptor (IGF1R. The data based on animal models and/or in vitro studies suggest the role of IGF system components in cellular aspects of hepatocarcinogenesis (cell cycle progression, uncontrolled proliferation, cell survival, migration, inhibition of apoptosis, protein synthesis and cell growth, and show that systemic IGF1 administration can reduce fibrosis and ameliorate general liver function. In epidemiologic and clinicopathological studies on chronic liver disease (CLD, lowered serum levels, decreased tissue expression of IGF1, elevated production of IGF1R and variable IGF2 expression has been noted, from the start of preneoplastic alterations up to the developed hepatocellular carcinoma (HCC stage. These changes result in well-known clinical symptoms of IGF1 deficiency. This review summarized the current data of the complex role of IGF system components in the most common CLD (nonalcoholic fatty liver disease, cirrhosis, and hepatocellular carcinoma. Better recognition and understanding of this system can contribute to discovery of new and improved versions of current preventive and therapeutic actions in CLD.

mTOR complex 2 phosphorylates IMP1 cotranslationally to promote IGF2 production and the proliferation of mouse embryonic fibroblasts

DEFF Research Database (Denmark)

Dai, Ning; Christiansen, Jan; Nielsen, Finn

2013-01-01

uncover a new mechanism by which mTOR regulates organismal growth by promoting IGF2 production in the mouse embryo through mTORC2-catalyzed cotranslational IMP1/IMP3 phosphorylation. Inasmuch as TORC2 is activated by association with ribosomes, the present results indicate that mTORC2-catalyzed...... production, and diminished proliferation. The proliferation of the IMP1-null fibroblasts can be restored to wild-type levels by IGF2 in vitro or by re-expression of IMP1, which corrects the defects in IGF2 RNA splicing and translation. The ability of IMP1 to correct these defects is dependent on IMP1...

The relevance of the M6P/IGF2R status for the tumorigenicity and invasiveness of liver and skin cancer cells

International Nuclear Information System (INIS)

Puxbaum, V.

2010-01-01

The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R), a multifunctional membrane-associated protein, plays a central role in targeting of lysosomal enzymes and controlling of the bioavailability of insulin-like growth factor II (IGF-II). In addition to intracellular sorting and endocytosis of M6P-containing ligands and IGF-II, the receptor also interacts with urokinase-type plasminogen activator receptor (uPAR) and plasminogen at the cell surface. M6P/IGF2R is considered a putative tumor suppressor, and its expression may modulate the invasiveness of cancer cells. Importantly, the M6P/IGF2R gene is frequently lost or mutated in a wide range of malignant tumors including hepatocellular and squamous cell carcinomas. However, the impact of the receptor on tumor invasion and metastasis is still poorly understood. FRL14 and SCC-VII cells are M6P/IGF2R deficient and thus secrete large amounts of lysosomal enzymes. Reconstitution of functional M6P/IGF2R expression restores transport of lysosomal enzymes to these compartments and drastically reduces the invasive potential of the cells. In addition, the presence of ectopic M6P/IGF2R compromises the growth of FRL14 and SCC-VII cells both in vitro and in vivo. Conversely, M6P/IGF2R knock-down in receptor-positive MIM-1-4 hepatocytes leads to increased lysosomal enzyme secretion and enhanced invasiveness. To assess the relevance of different ligand-binding sites for the biological activities of M6P/IGF2R, several mutant forms of the receptor were stably expressed in FRL14 and SCC-VII cells. Functional M6P-binding sites proved to be important for the anti-invasive potential of M6P/IGF2R, whereas the interactions of the receptor with IGF-II and uPAR/plasminogen were found to be dispensable for its biological activities. These results suggest that the M6P/IGF2R status influences the metastatic propensity of hepatocellular and squamous cell carcinomas, and that functional M6P-binding sites are crucial for the

Expression of insulin-like growth factor system components in colorectal tissue and its relation with serum IGF levels

NARCIS (Netherlands)

Vrieling, A.; Voskuil, D.W.; Bosma, A.; Majoor, D.M.; Doorn, van J.; Cats, A.; Depla, A.; Timmer, R.; Witteman, B.J.M.; Wesseling, J.; Kampman, E.; van't Veer, L.J.

2009-01-01

Context: The insulin-like growth factor (IGF)-system has been implicated in colorectal tumor carcinogenesis. Although both tumor expression levels and serum concentrations of IGF-system components are related to colorectal cancer risk, it is unknown whether IGF levels in tissue and serum are

Expression of insulin-like growth factor system components in colorectal tissue and its relation with serum IGF levels.

NARCIS (Netherlands)

Vrieling, A.; Voskuil, D.W.; Bosma, A.; Majoor, D.M.; Doorn, J. van; Cats, A.; Depla, A.C.; Timmer, R.; Witteman, B.J.; Wesseling, J.; Kampman, E.; Veer, L.J. van 't

2009-01-01

CONTEXT: The insulin-like growth factor (IGF)-system has been implicated in colorectal tumor carcinogenesis. Although both tumor expression levels and serum concentrations of IGF-system components are related to colorectal cancer risk, it is unknown whether IGF levels in tissue and serum are

Protein expression of VEGF, IGF-1 and FGF in retroocular connective tissues and clinical correlation in Graves' ophthalmopathy Expressão protéica de VEGF, IGF-1 e FGF no tecido conjuntivo retro-ocular e correlação clínica na oftalmopatia de Graves

Directory of Open Access Journals (Sweden)

Kimble Matos

2008-08-01

Full Text Available PURPOSE: To investigate the immunohistochemical expression (IGF-1, EGFr, EGF, c-erbB-2/HER-2/neu, PDGF-A, PDGF-B, FGF and VEGF in patients with Graves' ophthalmopathy. METHODS: Twenty-four samples (Graves' ophthalmopathy patients underwent lateral rectus muscle and surrounding fibrous and adipose tissue biopsy. The control group was obtained by strabismus surgery. Correlation between clinical- ophthalmologic, endocrinological, ultrasonographic findings, and immunohistochemical expression was performed. RESULTS: IGF-1: There were 7 positive cases (29.2%. There was a direct relation with higher CAS (clinical activity score in all of them and if only CAS equal or higher than 5 was considered, this was 54.5%. FGF: There was expression in 5 cases (20.8% with a direct relation in all those with higher CAS (>5 (45.4%. VEGF: There were two positive cases (8.3% for VEGF in endothelial cells, in these cases the patients also presented CAS higher than 5. There was no expressions of all growth factors in the control group. CONCLUSIONS: All patients, except one, with positive expression of FGF, IGF-1 and VEGF showed CAS greater than 5, suggesting in this way an important role of these growth factors in the pathogenesis and severity of Graves' ophthalmopathy. However, statistical analysis revealed only significant association between IGF-1 and male sex (P=0.034. Low ultrasound reflectivity and endocrine status may not correlate directly with disease activity or with immunoexpression of growth factors and c-erbB-2/HER-2/neu.OBJETIVO: Investigar a expressão imuno-histoquímica de IGF-1, EGFr, EGF, c-erbB-2/HER-2/neu, PDGF-A, PDGF-B, FGF e VEGF na oftalmopatia de Graves. MÉTODOS: Vinte e dois pacientes (oftalmopatia de Graves foram submetidos à biópsia do músculo reto lateral e tecido fibroso e adiposo adjacente. O grupo controle foi de pacientes de cirurgia de estrabismo. Foi feita correlação entre achados clínico-oftalmológicos, endocrinol

The Effects of IGF-1 on Trk Expressing DRG Neurons with HIV-gp120- Induced Neurotoxicity.

Science.gov (United States)

Li, Hao; Liu, Zhen; Chi, Heng; Bi, Yanwen; Song, Lijun; Liu, Huaxiang

2016-01-01

HIV envelope glycoprotein gp120 is the main protein that causes HIVassociated sensory neuropathy. However, the underlying mechanisms of gp120-induced neurotoxicity are still unclear. There are lack effective treatments for relieving HIV-related neuropathic symptoms caused by gp120-induced neurotoxicity. In the present study, tyrosine kinase receptor (Trk)A, TrkB, and TrkC expression in primary cultured dorsal root ganglion (DRG) neurons with gp120-induced neurotoxicity was investigated. The effects of IGF-1 on distinct Trk-positive DRG neurons with gp120-induced neurotoxicity were also determined. The results showed that gp120 not only dose-dependently induced DRG neuronal apoptosis and inhibited neuronal survival and neurite outgrowth, but also decreased distinct Trk expression levels. IGF-1 rescued DRG neurons from apoptosis and improved neuronal survival of gp120 neurotoxic DRG neurons in vitro. IGF-1 also improved TrkA and TrkB, but not TrkC, expression in gp120 neurotoxic conditions. The effects of IGF-1 could be blocked by preincubation with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. These results suggested that gp120 may have a wide range of neurotoxicity on different subpopulations of DRG neurons, while IGF-1 might only relieve some subpopulations of DRG neurons with gp120-induced neurotoxicity. These data provide novel information of mechanisms of gp120 neurotoxicity on primary sensory neurons and the potential therapeutic effects of IGF-1 on gp120-induced neurotoxicity.

IGF-1 Receptor Expression on Circulating Osteoblast Progenitor Cells Predicts Tissue-Based Bone Formation Rate and Response to Teriparatide in Premenopausal Women With Idiopathic Osteoporosis.

Science.gov (United States)

Cohen, Adi; Kousteni, Stavroula; Bisikirska, Brygida; Shah, Jayesh G; Manavalan, J Sanil; Recker, Robert R; Lappe, Joan; Dempster, David W; Zhou, Hua; McMahon, Donald J; Bucovsky, Mariana; Kamanda-Kosseh, Mafo; Stubby, Julie; Shane, Elizabeth

2017-06-01

We have previously reported that premenopausal women with idiopathic osteoporosis (IOP) have profound microarchitectural deficiencies and heterogeneous bone remodeling. Those with the lowest bone formation rate have higher baseline serum insulin-like growth factor-1 (IGF-1) levels and less robust response to teriparatide. Because IGF-1 stimulates bone formation and is critical for teriparatide action on osteoblasts, these findings suggest a state of IGF-1 resistance in some IOP women. To further investigate the hypothesis that osteoblast and IGF-1-related mechanisms mediate differential responsiveness to teriparatide in IOP, we studied circulating osteoblast progenitor (COP) cells and their IGF-1 receptor (IGF-1R) expression. In premenopausal women with IOP, peripheral blood mononuclear cells (PBMCs) were obtained at baseline (n = 25) and over 24 months of teriparatide treatment (n = 11). Flow cytometry was used to identify and quantify COPs (non-hematopoetic lineage cells expressing osteocalcin and RUNX2) and to quantify IGF-1R expression levels. At baseline, both the percent of PBMCs that were COPs (%COP) and COP cell-surface IGF-1R expression correlated directly with several histomorphometric indices of bone formation in tetracycline-labeled transiliac biopsies. In treated subjects, both %COP and IGF-1R expression increased promptly after teriparatide, returning toward baseline by 18 months. Although neither baseline %COP nor increase in %COP after 3 months predicted the bone mineral density (BMD) response to teriparatide, the percent increase in IGF-1R expression on COPs at 3 months correlated directly with the BMD response to teriparatide. Additionally, lower IGF-1R expression after teriparatide was associated with higher body fat, suggesting links between teriparatide resistance, body composition, and the GH/IGF-1 axis. In conclusion, these assays may be useful to characterize bone remodeling noninvasively and may serve to predict early response to

Zcchc11 Uridylates Mature miRNAs to Enhance Neonatal IGF-1 Expression, Growth, and Survival

Science.gov (United States)

Kozlowski, Elyse; Matsuura, Kori Y.; Ferrari, Joseph D.; Morris, Samantha A.; Powers, John T.; Daley, George Q.; Quinton, Lee J.; Mizgerd, Joseph P.

2012-01-01

The Zcchc11 enzyme is implicated in microRNA (miRNA) regulation. It can uridylate let-7 precursors to decrease quantities of the mature miRNA in embryonic stem cell lines, suggested to mediate stem cell maintenance. It can uridylate mature miR-26 to relieve silencing activity without impacting miRNA content in cancer cell lines, suggested to mediate cytokine and growth factor expression. Broader roles of Zcchc11 in shaping or remodeling the miRNome or in directing biological or physiological processes remain entirely speculative. We generated Zcchc11-deficient mice to address these knowledge gaps. Zcchc11 deficiency had no impact on embryogenesis or fetal development, but it significantly decreased survival and growth immediately following birth, indicating a role for this enzyme in early postnatal fitness. Deep sequencing of small RNAs from neonatal livers revealed roles of this enzyme in miRNA sequence diversity. Zcchc11 deficiency diminished the lengths and terminal uridine frequencies for diverse mature miRNAs, but it had no influence on the quantities of any miRNAs. The expression of IGF-1, a liver-derived protein essential to early growth and survival, was enhanced by Zcchc11 expression in vitro, and miRNA silencing of IGF-1 was alleviated by uridylation events observed to be Zcchc11-dependent in the neonatal liver. In neonatal mice, Zcchc11 deficiency significantly decreased IGF-1 mRNA in the liver and IGF-1 protein in the blood. We conclude that the Zcchc11-mediated terminal uridylation of mature miRNAs is pervasive and physiologically significant, especially important in the neonatal period for fostering IGF-1 expression and enhancing postnatal growth and survival. We propose that the miRNA 3′ terminus is a regulatory node upon which multiple enzymes converge to direct silencing activity and tune gene expression. PMID:23209448

Zcchc11 uridylates mature miRNAs to enhance neonatal IGF-1 expression, growth, and survival.

Directory of Open Access Journals (Sweden)

Matthew R Jones

Full Text Available The Zcchc11 enzyme is implicated in microRNA (miRNA regulation. It can uridylate let-7 precursors to decrease quantities of the mature miRNA in embryonic stem cell lines, suggested to mediate stem cell maintenance. It can uridylate mature miR-26 to relieve silencing activity without impacting miRNA content in cancer cell lines, suggested to mediate cytokine and growth factor expression. Broader roles of Zcchc11 in shaping or remodeling the miRNome or in directing biological or physiological processes remain entirely speculative. We generated Zcchc11-deficient mice to address these knowledge gaps. Zcchc11 deficiency had no impact on embryogenesis or fetal development, but it significantly decreased survival and growth immediately following birth, indicating a role for this enzyme in early postnatal fitness. Deep sequencing of small RNAs from neonatal livers revealed roles of this enzyme in miRNA sequence diversity. Zcchc11 deficiency diminished the lengths and terminal uridine frequencies for diverse mature miRNAs, but it had no influence on the quantities of any miRNAs. The expression of IGF-1, a liver-derived protein essential to early growth and survival, was enhanced by Zcchc11 expression in vitro, and miRNA silencing of IGF-1 was alleviated by uridylation events observed to be Zcchc11-dependent in the neonatal liver. In neonatal mice, Zcchc11 deficiency significantly decreased IGF-1 mRNA in the liver and IGF-1 protein in the blood. We conclude that the Zcchc11-mediated terminal uridylation of mature miRNAs is pervasive and physiologically significant, especially important in the neonatal period for fostering IGF-1 expression and enhancing postnatal growth and survival. We propose that the miRNA 3' terminus is a regulatory node upon which multiple enzymes converge to direct silencing activity and tune gene expression.

The anti-apoptotic effect of IGF-1 on tissue resident stem cells is mediated via PI3-kinase dependent secreted frizzled related protein 2 (Sfrp2) release

International Nuclear Information System (INIS)

Gehmert, Sebastian; Sadat, Sanga; Song Yaohua; Yan Yasheng; Alt, Eckhard

2008-01-01

Previous studies suggest that IGF-1 may be used as an adjuvant to stem cell transfer in order to improve cell engraftment in ischemic tissue. In the current study, we investigated the effect of IGF-1 on serum deprivation and hypoxia induced stem cell apoptosis and the possible mechanisms involved. Exposure of adipose tissue derived stem cells (ASCs) to serum deprivation and hypoxia resulted in significant apoptosis in ASC which is partially prevented by IGF-1. IGF-1's anti-apoptotic effect was abolished in ASCs transfected with Sfrp2 siRNA but not by the control siRNA. Using Western blot analysis, we demonstrated that serum deprivation and hypoxia reduced the expression of nuclear β-catenin, which is reversed by IGF-1. IGF-1's effect on β-catenin expression was abolished by the presence of PI3-kinase inhibitor LY294002 or in ASCs transfected with Sfrp2 siRNA. These results suggest that IGF-1, through the release of the Sfrp2, contributes to cell survival by stabilizing β-catenin

Increased linear bone growth by GH in the absence of SOCS2 is independent of IGF-1.

Science.gov (United States)

Dobie, Ross; Ahmed, Syed F; Staines, Katherine A; Pass, Chloe; Jasim, Seema; MacRae, Vicky E; Farquharson, Colin

2015-11-01

Growth hormone (GH) signaling is essential for postnatal linear bone growth, but the relative importance of GHs actions on the liver and/or growth plate cartilage remains unclear. The importance of liver derived insulin like-growth factor-1 (IGF-1) for endochondral growth has recently been challenged. Here, we investigate linear growth in Suppressor of Cytokine Signaling-2 (SOCS2) knockout mice, which have enhanced growth despite normal systemic GH/IGF-1 levels. Wild-type embryonic ex vivo metatarsals failed to exhibit increased linear growth in response to GH, but displayed increased Socs2 transcript levels (P growth over a 12 day period. Despite this increase, IGF-1 transcript and protein levels were not increased in response to GH. In accordance with these data, IGF-1 levels were unchanged in GH-challenged postnatal Socs2(-/-) conditioned medium despite metatarsals showing enhanced linear growth. Growth-plate Igf1 mRNA levels were not elevated in juvenile Socs2(-/-) mice. GH did however elevate IGF-binding protein 3 levels in conditioned medium from GH challenged metatarsals and this was more apparent in Socs2(-/-) metatarsals. GH did not enhance the growth of Socs2(-/-) metatarsals when the IGF receptor was inhibited, suggesting that IGF receptor mediated mechanisms are required. IGF-2 may be responsible as IGF-2 promoted metatarsal growth and Igf2 expression was elevated in Socs2(-/-) (but not WT) metatarsals in response to GH. These studies emphasise the critical importance of SOCS2 in regulating GHs ability to promote bone growth. Also, GH appears to act directly on the metatarsals of Socs2(-/-) mice, promoting growth via a mechanism that is independent of IGF-1. © 2014 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Inter- and intra-individual variation in allele-specific DNA methylation and gene expression in children conceived using assisted reproductive technology.

Directory of Open Access Journals (Sweden)

Nahid Turan

2010-07-01

Full Text Available Epidemiological studies have reported a higher incidence of rare disorders involving imprinted genes among children conceived using assisted reproductive technology (ART, suggesting that ART procedures may be disruptive to imprinted gene methylation patterns. We examined intra- and inter-individual variation in DNA methylation at the differentially methylated regions (DMRs of the IGF2/H19 and IGF2R loci in a population of children conceived in vitro or in vivo. We found substantial variation in allele-specific methylation at both loci in both groups. Aberrant methylation of the maternal IGF2/H19 DMR was more common in the in vitro group, and the overall variance was also significantly greater in the in vitro group. We estimated the number of trophoblast stem cells in each group based on approximation of the variance of the binomial distribution of IGF2/H19 methylation ratios, as well as the distribution of X chromosome inactivation scores in placenta. Both of these independent measures indicated that placentas of the in vitro group were derived from fewer stem cells than the in vivo conceived group. Both IGF2 and H19 mRNAs were significantly lower in placenta from the in vitro group. Although average birth weight was lower in the in vitro group, we found no correlation between birth weight and IGF2 or IGF2R transcript levels or the ratio of IGF2/IGF2R transcript levels. Our results show that in vitro conception is associated with aberrant methylation patterns at the IGF2/H19 locus. However, very little of the inter- or intra-individual variation in H19 or IGF2 mRNA levels can be explained by differences in maternal DMR DNA methylation, in contrast to the expectations of current transcriptional imprinting models. Extraembryonic tissues of embryos cultured in vitro appear to be derived from fewer trophoblast stem cells. It is possible that this developmental difference has an effect on placental and fetal growth.

IGF-1R Regulates the Extracellular Level of Active MMP-2, Pathological Neovascularization, and Functionality in Retinas of OIR Mouse Model.

Science.gov (United States)

Lorenc, Valeria E; Subirada Caldarone, Paula V; Paz, María C; Ferrer, Darío G; Luna, José D; Chiabrando, Gustavo A; Sánchez, María C

2018-02-01

In ischemic proliferative diseases such as retinopathies, persistent hypoxia leads to the release of numerous neovascular factors that participate in the formation of abnormal vessels and eventually cause blindness. The upregulation and activation of metalloproteinases (MMP-2 and MMP-9) represent a final common pathway in this process. Although many regulators of the neovascular process have been identified, the complete role of the insulin-like growth factor 1 (IGF-1) and its receptor (IGF-1R) appears to be significantly more complex. In this study, we used an oxygen-induced retinopathy (OIR) mouse model as well as an in vitro model of hypoxia to study the role of MMP-2 derived from Müller glial cells (MGCs) and its relation with the IGF-1/IGF-1R system. We demonstrated that MMP-2 protein expression increased in P17 OIR mice, which coincided with the active phase of the neovascular process. Also, glutamine synthetase (GS)-positive cells were also positive for MMP-2, whereas IGF-1R was expressed by GFAP-positive cells, indicating that both proteins were expressed in MGCs. In addition, in the OIR model a single intravitreal injection of the IGF-1R blocking antibody (αIR3) administered at P12 effectively prevented pathologic neovascularization, accelerated physiological revascularization, and improved retinal functionality at P17. Finally, in MGC supernatants, the blocking antibody abolished the IGF-1 effect on active MMP-2 under normoxic and hypoxic conditions without affecting the extracellular levels of pro-MMP-2. These results demonstrate, for the first time, that the IGF-1/IGF-1R system regulates active MMP-2 levels in MGCs, thus contributing to MEC remodeling during the retinal neovascular process.

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes.

Science.gov (United States)

Liu, Ping; Kong, Feng; Wang, Jue; Lu, Qinghua; Xu, Haijia; Qi, Tonggang; Meng, Juan

2015-02-01

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0-G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. Copyright © 2014 Elsevier Inc. All rights reserved.

IGF-1-induced MMP-11 expression promotes the proliferation and invasion of gastric cancer cells through the JAK1/STAT3 signaling pathway.

Science.gov (United States)

Su, Chao; Wang, Wenchang; Wang, Cunchuan

2018-05-01

The present study aimed to investigate the association between insulin-like growth factor-1 (IGF-1) and matrix metalloproteinase-11 (MMP-11) expression in gastric cancer (GC) and the underlying mechanisms in SGC-7901 cells. Reverse transcription-quantitative polymerase chain reaction analysis revealed that the expression of IGF-1 and MMP-11 was significantly upregulated in GC tissues compared with normal gastric tissue. Furthermore, IGF-1 significantly and dose-dependently promoted MMP-11. Western blotting revealed that the addition of IGF-1 to SGC-7901 cells led to an evident enhancement in signal transducer and activator of transcription 3 (STAT3), IGF-1R and Janus kinase 1 (JAK1) phosphorylation at 20 and 40 min. A decrease in the extent of the elevated expression of MMP-11 and the enhanced phosphorylation of STAT3, JAK1 and IGF-1 receptor (IGF-1R) induced by IGF-1 in SGC-7901 cells were observed following treatment with NT157 (an IGF-1R inhibitor). Furthermore, piceatannol (a JAK1 inhibitor) or small interfering RNA against STAT3 reduced the extent of the increased expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Piceatannol treatment induced the dose-dependent decline in the enhancement of STAT3 phosphorylation induced by IGF-1, indicating that the JAK1/STAT3 pathway may be implicated in the elevated expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Finally, IGF-1 treatment significantly promoted the proliferation and invasion of SGC-7901 cells, which was inhibited following NT157, piceatannol or si-STAT3 treatment. The present study therefore demonstrated that IGF-1-induced MMP-11 may have facilitated the proliferation and invasion of SGC-7901 cells via the JAK1/STAT3 pathway.

Clinical significance of changes of serum expression of IGF-I in patients with astrocytoma

International Nuclear Information System (INIS)

Liu Jianbo; Ding Dongmei; Yang Fubing

2005-01-01

Objective: To investigate the serum expression of IGF-I in patients with astrocytoma of different degrees of malignancy as well as the changes of levels after operative removal of the tumor. Methods: Serum IGF-I contents were measured with IRMA in 16 patients with Grade I-II astrocytoma and 14 patients with Grade III-IV astrocytoma both before and after operation as well as in 30 controls. Results: The serum contents of IGF-I in both groups of patients were significantly higher than those in controls (P<0.05). The levels in Grade III-IV patients were significantly higher than those in Grade I-II patients (P < 0.05 ). After operation, the levels dropped significantly (vs before operation, P<0.05). Conclusion: The serum contents of IGF - I in patients with astrocytoma were positively correlated with the degree of malignancy. Post-operative decrease of IGF-I contents was related to the decrease of tumor burden. (authors)

Recent acquisition of imprinting at the rodent Sfmbt2 locus correlates with insertion of a large block of miRNAs

Directory of Open Access Journals (Sweden)

Chung Eu Ddeum

2011-04-01

Full Text Available Abstract Background The proximal region of murine Chr 2 has long been known to harbour one or more imprinted genes from classic genetic studies involving reciprocal translocations. No imprinted gene had been identified from this region until our study demonstrated that the PcG gene Sfmbt2 is expressed from the paternally inherited allele in early embryos and extraembryonic tissues. Imprinted genes generally reside in clusters near elements termed Imprinting Control Regions (ICRs, suggesting that Sfmbt2 might represent an anchor for a new imprinted domain. Results We analyzed allelic expression of approximately 20 genes within a 3.9 Mb domain and found that Sfmbt2 and an overlapping non-coding antisense transcript are the only imprinted genes in this region. These transcripts represent a very narrow imprinted gene locus. We also demonstrate that rat Sfmbt2 is imprinted in extraembryonic tissues. An interesting feature of both mouse and rat Sfmbt2 genes is the presence of a large block of miRNAs in intron 10. Other mammals, including the bovine, lack this block of miRNAs. Consistent with this association, we show that human and bovine Sfmbt2 are biallelic. Other evidence indicates that pig Sfmbt2 is also not imprinted. Further strengthening the argument for recent evolution of Sfmbt2 is our demonstration that a more distant muroid rodent, Peromyscus also lacks imprinting and the block of miRNAs. Conclusions These observations are consistent with the hypothesis that the block of miRNAs are driving imprinting at this locus. Our results are discussed in the context of ncRNAs at other imprinted loci. Accession numbers for Peromyscus cDNA and intron 10 genomic DNA are [Genbank:HQ416417 and Genbank:HQ416418], respectively.

IGF-1 Promotes Brn-4 Expression and Neuronal Differentiation of Neural Stem Cells via the PI3K/Akt Pathway

Science.gov (United States)

Zhang, Xinhua; Zhang, Lei; Cheng, Xiang; Guo, Yuxiu; Sun, Xiaohui; Chen, Geng; Li, Haoming; Li, Pengcheng; Lu, Xiaohui; Tian, Meiling; Qin, Jianbing; Zhou, Hui; Jin, Guohua

2014-01-01

Our previous studies indicated that transcription factor Brn-4 is upregulated in the surgically denervated hippocampus in vivo, promoting neuronal differentiation of hippocampal neural stem cells (NSCs) in vitro. The molecules mediating Brn-4 upregulation in the denervated hippocampus remain unknown. In this study we examined the levels of insulin-like growth factor-1 (IGF-1) in hippocampus following denervation. Surgical denervation led to a significant increase in IGF-1 expression in vivo. We also report that IGF-1 treatment on NSCs in vitro led to a marked acceleration of Brn-4 expression and cell differentiation down neuronal pathways. The promotion effects were blocked by PI3K-specific inhibitor (LY294002), but not MAPK inhibitor (PD98059); levels of phospho-Akt were increased by IGF-1 treatment. In addition, inhibition of IGF-1 receptor (AG1024) and mTOR (rapamycin) both attenuated the increased expression of Brn-4 induced by IGF-1. Together, the results demonstrated that upregulation of IGF-1 induced by hippocampal denervation injury leads to activation of the PI3K/Akt signaling pathway, which in turn gives rise to upregulation of the Brn-4 and subsequent stem cell differentiation down neuronal pathways. PMID:25474202

Gene expression profiling of preovulatory follicle in the buffalo cow: effects of increased IGF-I concentration on periovulatory events.

Directory of Open Access Journals (Sweden)

Jyotsna U Rao

Full Text Available The preovulatory follicle in response to gonadotropin surge undergoes dramatic biochemical, and morphological changes orchestrated by expression changes in hundreds of genes. Employing well characterized bovine preovulatory follicle model, granulosa cells (GCs and follicle wall were collected from the preovulatory follicle before, 1, 10 and 22 h post peak LH surge. Microarray analysis performed on GCs revealed that 450 and 111 genes were differentially expressed at 1 and 22 h post peak LH surge, respectively. For validation, qPCR and immunocytochemistry analyses were carried out for some of the differentially expressed genes. Expression analysis of many of these genes showed distinct expression patterns in GCs and the follicle wall. To study molecular functions and genetic networks, microarray data was analyzed using Ingenuity Pathway Analysis which revealed majority of the differentially expressed genes to cluster within processes like steroidogenesis, cell survival and cell differentiation. In the ovarian follicle, IGF-I is established to be an important regulator of the above mentioned molecular functions. Thus, further experiments were conducted to verify the effects of increased intrafollicular IGF-I levels on the expression of genes associated with the above mentioned processes. For this purpose, buffalo cows were administered with exogenous bGH to transiently increase circulating and intrafollicular concentrations of IGF-I. The results indicated that increased intrafollicular concentrations of IGF-I caused changes in expression of genes associated with steroidogenesis (StAR, SRF and apoptosis (BCL-2, FKHR, PAWR. These results taken together suggest that onset of gonadotropin surge triggers activation of various biological pathways and that the effects of growth factors and peptides on gonadotropin actions could be examined during preovulatory follicle development.

IGF-1 protects against Aβ25-35-induced neuronal cell death via inhibition of PUMA expression and Bax activation.

Science.gov (United States)

Hou, Xunyao; Jin, Yan; Chen, Jian; Hong, Yan; Luo, Dingzhen; Yin, Qingqing; Liu, Xueping

2017-01-10

Amyloid-β-peptide (Aβ) is considered to be the toxic species in AD and causes cell death in the affected areas of patient's brain. Insulin-like growth factor 1 (IGF-1) has been reported to attenuate Aβ toxicity in neuronal cells. However, the molecular mechanisms involved in the neuroprotective function of IGF-1 remain largely unknown. In the present study, we for the first time demonstrated that IGF-1 protects against Aβ-induced neurotoxicity via inhibition of PUMA expression and Bax activation. We found that IGF-1 could activate Akt, which in turn inhibited Aβ-induced FOXO3a nuclear translocation and thus decreased the binding ability of FOXO3a to PUMA promoter, leading to decreased PUMA expression. In addition, IGF-1 inhibited the translocation of Bax to the mitochondria induced by Aβ. Notably, addition of wortmannin, a specific inhibitor of PI3K, significantly abolished the neuroprotective effect of IGF-1, suggesting that IGF-1 exerts its anti-apoptotic effect depend on PI3K activity. Our findings may provide new insights into molecular mechanisms mediated by IGF-1 in cell survival against Aβ-induced apoptosis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon

DEFF Research Database (Denmark)

Heinemeier, K M; Olesen, J L; Schjerling, P

2007-01-01

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regul......In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types...... on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius......, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P

The relationship between maternal insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and IGFBP-3 to gestational age and preterm delivery.

LENUS (Irish Health Repository)

Cooley, Sharon M

2012-02-01

AIMS: To investigate the relationship between levels of insulin-like growth factors 1 and 2 (IGF-1, IGF-2), and insulin-like growth factor binding protein 3 (IGFBP-3) in antenatal maternal serum and gestational age at delivery. METHODS: Prospective cohort study of 1650 low-risk Caucasian women in a London University teaching hospital. Maternal IGF-1, IGF-2 and IGFBP-3 were measured in maternal blood at booking and analyzed with respect to gestational age at delivery. RESULTS: There was no significant association between maternal IGF-1 or IGF-2 and preterm birth (PTB). A significant reduction in mean IGFBP-3 levels was noted with delivery <32 completed weeks (P=0.02). CONCLUSION: Maternal mean IGFBP-3 levels are significantly reduced in cases complicated by delivery <32 completed weeks.

Takifugu rubripes cation independent mannose 6-phosphate receptor: Cloning, expression and functional characterization of the IGF-II binding domain.

Science.gov (United States)

A, Ajith Kumar; Nadimpalli, Siva Kumar

2018-07-01

Mannose 6-phosphate/IGF-II receptor mediated lysosomal clearance of insulin-like growth factor-II is significantly associated with the evolution of placental mammals. The protein is also referred to as the IGF-II receptor. Earlier studies suggested relatively low binding affinity between the receptor and ligand in prototherian and metatherian mammals. In the present study, we cloned the IGF-II binding domain of the early vertebrate fugu fish and expressed it in bacteria. A 72000Da truncated receptor containing the IGF-II binding domain was obtained. Analysis of this protein (covering domains 11-13 of the CIMPR) for its affinity to fish and human IGF-II by ligand blot assays and ELISA showed that the expressed receptor can specifically bind to both fish and human IGF-II. Additionally, a peptide-specific antibody raised against the region of the IGF-II binding domain also was able to recognize the IGF-II binding regions of mammalian and non-mammalian cation independent MPR protein. These interactions were further characterized by Surface Plasma resonance support that the receptor binds to fish IGF-II, with a dissociation constant of 548nM. Preliminary analysis suggests that the binding mechanism as well as the affinity of the fish and human receptor for IGF-II may have varied according to different evolutionary pressures. Copyright © 2018. Published by Elsevier B.V.

Studies on Expression of IGF-II Gene in Deciduas Derived from Medical Abortion Patients

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

Objective To determine the effect of insulin-like growth factor-Ⅱ (IGF-Ⅱ ) upon the maintenance of decidua in early pregnancy and its relationship with progesterone, as well as its role in medical abortion. Materials & Methods Decidua tissue was obtained from 28 women who undergoing surgical abortion and 39 for medical abortion respectively at 5～7 weeks of gestation. The extracted total RNA was reversely transcripted and amplified by PCR with spe cific primers (IGF-Ⅱ and β-actin). The products were semi-quantitated by MIAS 300 system and qualitatively analyzed by southern blotting. Results The expression of IGF-Ⅱ gene in decidua from surgical abortion was signif icantly higher than that from medical abortion (P＜0.05). The average IGF-Ⅱ gene transcription values were 1. 54±0.79 and 0.72±0.39 respectively. The results of southern blotting proved qualitatively that the RT-PCR products were IGF-Ⅱ cDNA. Conclusion IGF-Ⅱ plays a role in the maintenance of decidua in early pregnancy. It may act as a mediator of progestin. It's also involved in the molecular mechanism of mifepristone.

E-Peptides Control Bioavailability of IGF-1

Science.gov (United States)

Piszczek, Agnieszka; Perlas, Emarald; Winn, Nadine; Nastasi, Tommaso; Rosenthal, Nadia

2012-01-01

Insulin-like growth factor 1 (IGF-1) is a potent cytoprotective growth factor that has attracted considerable attention as a promising therapeutic agent. Transgenic over-expression of IGF-1 propeptides facilitates protection and repair in a broad range of tissues, although transgenic mice over-expressing IGF-1 propeptides display little or no increase in IGF-1 serum levels, even with high levels of transgene expression. IGF-1 propeptides are encoded by multiple alternatively spliced transcripts including C-terminal extension (E) peptides, which are highly positively charged. In the present study, we use decellularized mouse tissue to show that the E-peptides facilitate in vitro binding of murine IGF-1 to the extracellular matrix (ECM) with varying affinities. This property is independent of IGF-1, since proteins consisting of the E-peptides fused to relaxin, a related member of the insulin superfamily, bound equally avidly to decellularized ECM. Thus, the E-peptides control IGF-1 bioavailability by preventing systemic circulation, offering a potentially powerful way to tether IGF-1 and other therapeutic proteins to the site of synthesis and/or administration. PMID:23251442

Epigenetic Mechanisms of Genomic Imprinting: Common Themes in the Regulation of Imprinted Regions in Mammals, Plants, and Insects

Directory of Open Access Journals (Sweden)

William A. MacDonald

2012-01-01

Full Text Available Genomic imprinting is a form of epigenetic inheritance whereby the regulation of a gene or chromosomal region is dependent on the sex of the transmitting parent. During gametogenesis, imprinted regions of DNA are differentially marked in accordance to the sex of the parent, resulting in parent-specific expression. While mice are the primary research model used to study genomic imprinting, imprinted regions have been described in a broad variety of organisms, including other mammals, plants, and insects. Each of these organisms employs multiple, interrelated, epigenetic mechanisms to maintain parent-specific expression. While imprinted genes and imprint control regions are often species and locus-specific, the same suites of epigenetic mechanisms are often used to achieve imprinted expression. This review examines some examples of the epigenetic mechanisms responsible for genomic imprinting in mammals, plants, and insects.

IGF-1 promotes Brn-4 expression and neuronal differentiation of neural stem cells via the PI3K/Akt pathway.

Directory of Open Access Journals (Sweden)

Xinhua Zhang

Full Text Available Our previous studies indicated that transcription factor Brn-4 is upregulated in the surgically denervated hippocampus in vivo, promoting neuronal differentiation of hippocampal neural stem cells (NSCs in vitro. The molecules mediating Brn-4 upregulation in the denervated hippocampus remain unknown. In this study we examined the levels of insulin-like growth factor-1 (IGF-1 in hippocampus following denervation. Surgical denervation led to a significant increase in IGF-1 expression in vivo. We also report that IGF-1 treatment on NSCs in vitro led to a marked acceleration of Brn-4 expression and cell differentiation down neuronal pathways. The promotion effects were blocked by PI3K-specific inhibitor (LY294002, but not MAPK inhibitor (PD98059; levels of phospho-Akt were increased by IGF-1 treatment. In addition, inhibition of IGF-1 receptor (AG1024 and mTOR (rapamycin both attenuated the increased expression of Brn-4 induced by IGF-1. Together, the results demonstrated that upregulation of IGF-1 induced by hippocampal denervation injury leads to activation of the PI3K/Akt signaling pathway, which in turn gives rise to upregulation of the Brn-4 and subsequent stem cell differentiation down neuronal pathways.

c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Hwang, Pyoung-Han [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Research Institute of Clinical Medicine, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Yi, Ho-Keun [Department of Biochemistry, School of Dentistry, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Nam, Sang-Yun [Department of Alternative Therapy, School of Alternative Medicine and Health Science, Jeonju University, Jeonju 561-712 (Korea, Republic of); Lee, Dae-Yeol, E-mail: leedy@chonbuk.ac.kr [Department of Pediatrics, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of); Research Institute of Clinical Medicine, School of Medicine, Chonbuk National University, Jeonju 561-712 (Korea, Republic of)

2009-07-17

c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.

c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

International Nuclear Information System (INIS)

Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh; Hwang, Pyoung-Han; Yi, Ho-Keun; Nam, Sang-Yun; Lee, Dae-Yeol

2009-01-01

c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.

A preliminary study of pamidronic acid downregulation of angiogenic factors IGF-1/PECAM-1 expression in circulating level in bone metastatic breast cancer patients

Directory of Open Access Journals (Sweden)

Wang Z

2016-05-01

Full Text Available Zeng Wang,1,2 Lei Lei,2,3 Xin-jun Cai,4 Ling Ya Chen,1,2 Meiqin Yuan,2,3 Guonong Yang,1,2 Ping Huang,1,2 Xiaojia Wang2,3 1Department of Pharmacy, 2Zhejiang Key Lab of Diagnosis & Treatment Technology on Thoracic Oncology, 3Department of Chemotherapy Center, Zhejiang Cancer Hospital, 4Department of Pharmacy, Integrated Chinese and Western Medicine Hospital of Zhejiang Province, Hangzhou, Zhejiang, People’s Republic of China Objective: To evaluate the expressions of circulating angiogenic factors affected by pamidronic acid (PA intravenous infusion in bone metastatic breast cancer patients and the impact on their prognosis.Methods: Peripheral blood of ten bone metastatic breast cancer patients was collected for serum insulin-like growth factor-1 (IGF-1 and platelet endothelial cell adhesion molecule-1 expression detection just before and 2 days after PA infusion.Results: Both IGF-1 and platelet endothelial cell adhesion molecule-1 concentrations decreased after PA treatment for 48 hours (P<0.05. Modification was defined as >20% decrease recorded 2 days after PA administration. The decrease of IGF-1 was more significant in breast cancer patients who had received previous hormonotherapy. Moreover, the progression-free survival of first-line chemotherapy treatment of IGF-1 modified patients was longer than that of IGF-1 unmodified patients (P=0.009.Conclusion: PA treatment could suppress circulating serum IGF-1 and platelet endothelial cell adhesion molecule-1 concentrations; moreover, the prognosis of patients in IGF-1 unmodified group was relatively poor. Keywords: pamidronic acid, insulin-like growth factor-1, platelet endothelial cell adhesion molecule-1, bone metastatic breast cancer, prognosis

The impact of IGF-1R expression on the outcomes of patients with breast cancer: a meta-analysis

Directory of Open Access Journals (Sweden)

Yan S

2015-01-01

Full Text Available Shunchao Yan,1 Xin Jiao,2 Kai Li,1 Wusheng Li,1 Huawei Zou11Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People’s Republic of China; 2Department of Respiratory Medicine, Shenyang Chest Hospital, Shenyang, People’s Republic of ChinaPurpose: The value of insulin-like growth factor 1 receptor (IGF-1R for predicting survival of patients with breast cancer remains controversial. The purpose of this study was to perform a meta-analysis of the published data to attempt to clarify the impact of IGF-1R.Methods: Studies published between January 1, 1990 and October 1, 2014 were identified using an electronic search to aggregate the available survival results. Studies were included if they reported detecting IGF-1R expression in the primary breast cancer and analyzed patient survival data according to IGF-1R status. The principal outcome measures were hazard ratios (HRs for survival of IGF-1R-positive patients. Combined HRs and 95% confidence intervals (CIs were estimated using fixed- or random-effects models according to between-study heterogeneity.Results: Ten studies, involving 5,406 patients, satisfied our inclusion criteria. Data from five studies provided the impact of IGF-1R on overall survival (OS, three studies the impact on breast cancer-specific survival (BCSS, and seven studies the impact on disease-free survival (DFS. The results of meta-analysis showed that for DFS, membranous IGF-1R positivity was not a significant predictor. The combined HR for OS/BCSS was 0.63 (95% CI: 0.42–0.95, P=0.03, indicating that membranous IGF-1R positivity was a significant predictor of better survival. IGF-1R cytoplasmic positivity was significantly associated with longer DFS and OS/BCSS (combined HR: 0.56, 95% CI: 0.35–0.89, P=0.01; combined HR: 0.55, 95% CI: 0.35–0.85, P=0.008, respectively. The results of subgroup analysis suggested that membranous IGF-1R positivity in hormone-receptor-positive breast cancer was

Targeted mass spectrometry analysis of the proteins IGF1, IGF2, IBP2, IBP3 and A2GL by blood protein precipitation

DEFF Research Database (Denmark)

Such-Sanmartín, Gerard; Bache, Nicolai; Callesen, Anne K

2015-01-01

aggravated when using fast high-throughput methods, which are necessary for analysis of hundreds and thousands of samples in clinical laboratories. The blood proteins IGF1, IGF2, IBP2, IBP3 and A2GL have been proposed as indirect biomarkers for detection of GH administration and as putative biomarkers...

Expression of insulin-like growth factor-2 receptors on EL4 lymphoma cells overexpressing growth hormone.

Science.gov (United States)

Farmer, John T; Weigent, Douglas A

2007-01-01

In the present study, we report the upregulation of functional IGF-2Rs in cells overexpressing growth hormone (GH). EL4 lymphoma cells stably transfected with an rGH cDNA overexpression vector (GHo) exhibited an increase in the binding of (125)I-IGF-2 with no change in the binding affinity compared to vector alone controls. An increase in the expression of the insulin-like growth factor-2 receptor (IGF-2R) in cells overexpressing GH was confirmed by Western blot analysis and IGF-2R promoter luciferase assays. EL4 cells produce insulin-like growth factor-2 (IGF-2) as detected by the reverse transcription-polymerase chain reaction (RT-PCR); however, no IGF-2 protein was detected by Western analysis. The increase in the expression of the IGF-2R resulted in greater levels of IGF-2 uptake in GHo cells compared to vector alone controls. The data suggest that one of the consequences of the overexpression of GH is an increase in the expression of the IGF-2R.

Early embryonic failure: Expression and imprinted status of candidate genes on human chromosome 21

Energy Technology Data Exchange (ETDEWEB)

Sherman, L.S.; Bennett, P.R.; Moore, G.E. [Queen Charlotte`s and Chelsea Hospital, London (United Kingdom)

1994-09-01

Two cases of maternal uniparental (hetero)disomy for human chromosome 21 (mUPD21) have been identified in a systematic search for UPD in 23 cases of early embryonic failure (EEF). Bi-parental origin of the other chromosome pairs was confirmed using specific VNTR probes or dinucleotide repeat analysis. Both maternally and paternally derived isochromosomes 21q have previously been identified in two individuals with normal phenotypes. Full UPD21 has a different mechanism of origin than uniparental isochromosome 21q and its effect on imprinted genes and phenotypic outcome will therefore not necessarily be the same. EEF associated with mUPD21 suggests that developmentally important genes on HSA 21 may be imprinted such that they are only expressed from either the maternally or paternally derived alleles. We have searched for monoallelic expression of candidate genes on HSA 21 in human pregnancy (CBS, IFNAR, COL6A1) using intragenic DNA polymorphisms. These genes were chosen either because their murine homologues lie in imprinted regions or because they are potentially important in embryogenesis. Once imprinted candidate genes have been identified, their methylation status and expression in normal, early embryonic failure and uniparental disomy 21 pregnancies will be studied. At the same time, a larger number of cases of EEF are being examined to further investigate the incidence of UPD21 in this group.

MicroRNA-214 Reduces Insulin-like Growth Factor-1 (IGF-1) Receptor Expression and Downstream mTORC1 Signaling in Renal Carcinoma Cells*

Science.gov (United States)

Das, Falguni; Dey, Nirmalya; Bera, Amit; Kasinath, Balakuntalam S.; Ghosh-Choudhury, Nandini; Choudhury, Goutam Ghosh

2016-01-01

Elevated IGF-1/insulin-like growth factor-1 receptor (IGF-1R) autocrine/paracrine signaling in patients with renal cell carcinoma is associated with poor prognosis of the disease independent of their von Hippel-Lindau (VHL) status. Increased expression of IGF-1R in renal cancer cells correlates with their potency of tumor development and progression. The mechanism by which expression of IGF-1R is increased in renal carcinoma is not known. We report that VHL-deficient and VHL-positive renal cancer cells possess significantly decreased levels of mature, pre-, and pri-miR-214 than normal proximal tubular epithelial cells. We identified an miR-214 recognition element in the 3′UTR of IGF-1R mRNA and confirmed its responsiveness to miR-214. Overexpression of miR-214 decreased the IGF-1R protein levels, resulting in the inhibition of Akt kinase activity in both types of renal cancer cells. IGF-1 provoked phosphorylation and inactivation of PRAS40 in an Akt-dependent manner, leading to the activation of mTORC1 signal transduction to increase phosphorylation of S6 kinase and 4EBP-1. Phosphorylation-deficient mutants of PRAS40 and 4EBP-1 significantly inhibited IGF-1R-driven proliferation of renal cancer cells. Expression of miR-214 suppressed IGF-1R-induced phosphorylation of PRAS40, S6 kinase, and 4EBP-1, indicating inhibition of mTORC1 activity. Finally, miR-214 significantly blocked IGF-1R-forced renal cancer cell proliferation, which was reversed by expression of 3′UTR-less IGF-1R and constitutively active mTORC1. Together, our results identify a reciprocal regulation of IGF-1R levels and miR-214 expression in renal cancer cells independent of VHL status. Our data provide evidence for a novel mechanism for IGF-1R-driven renal cancer cell proliferation involving miR-214 and mTORC1. PMID:27226530

[Differential expression of IGF-I and its mRNA in mandibular condylar cartilage of rat--direct evidence for servosystem theory of facial growth].

Science.gov (United States)

Zhou, Z; Luo, S

1998-05-01

It was studied the expression of IGF-I and its mRNA in the condylar cartilage of 10 7-week-old SD male rats by using in situ hybridization and immunohisto-chemistry technique. The results showed both IGF-I and its gene expressed in growing rat condyle. IGF-I peptide was abundant in germinal zone, and positive reaction of its mRNA was strongest in transitional and maturational zones. These indicate that condylar cartilage has the capability of local production and secretion of IGF-I, mediating the command effect of STH, and differential expression of IGF-I and its mRNA might establish the local feedback loop, which supply a direct evidence for servosystem theory of facial growth.

The impact of IGF-1R expression on the outcomes of patients with breast cancer: a meta-analysis

Science.gov (United States)

Yan, Shunchao; Jiao, Xin; Li, Kai; Li, Wusheng; Zou, Huawei

2015-01-01

IGF-1R positivity in Her-2-positive or ER (estrogen receptor)-negative breast cancer was not found to be a significant prognostic indicator. Conclusion The results of this meta-analysis suggest that IGF-1R expression has different prognostic values for patients with breast cancers of different molecular subtypes. It was a favorable prognostic indicator in unselected breast cancers and hormone-receptor-positive cancers, but indicated poor survival in triple-negative breast cancers. PMID:25674003

Telomerase activity promotes osteoblast differentiation by modulating IGF-signaling pathway

DEFF Research Database (Denmark)

Saeed, Hamid; Qiu, Weimin; Li, Chen

2015-01-01

-regulation of several components of insulin-like growth factor (IGF) signaling. Specifically, a significant increase in IGF-induced AKT phosphorylation and alkaline phosphatase (ALP) activity were observed in hMSC-TERT. Enhanced ALP activity was reduced in presence of IGF1 receptor inhibitor: picropodophyllin....... In addition, telomerase deficiency caused significant reduction in IGF signaling proteins in osteoblastic cells cultured from telomerase deficient mice (Terc (-/-)). The low bone mass exhibited by Terc (-/-) mice was associated with significant reduction in serum levels of IGF1 and IGFBP3 as well as reduced...... skeletal mRNA expression of Igf1, Igf2, Igf2r, Igfbp5 and Igfbp6. IGF1-induced osteoblast differentiation was also impaired in Terc (-/-) MSC. In conclusion, our data demonstrate that impaired IGF/AKT signaling contributes to the observed decreased bone mass and bone formation exhibited by telomerase...

Stocking density affects the growth performance and metabolism of Amur sturgeon by regulating expression of genes in the GH/IGF axis

Science.gov (United States)

Ren, Yuanyuan; Wen, Haishen; Li, Yun; Li, Jifang

2017-07-01

The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three different stocking densities (low stocking density, LSD: 5.5 kg/m3; medium stocking density, MSD: 8.0 kg/m3; and high stocking density, HSD: 11.0 kg/m3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower final body weight and specific growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2 (IGF-2), while the concentrations of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) decreased in the HSD group. The full-length cDNAs of GH and IGF-2 genes (995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor (GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively affects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.

ZBED6, a novel transcription factor derived from a domesticated DNA transposon regulates IGF2 expression and muscle growth

DEFF Research Database (Denmark)

Markljung, Ellen; Jiang, Lin; Jaffe, Jacob D

2009-01-01

and find that the protein, named ZBED6, is previously unknown, specific for placental mammals, and derived from an exapted DNA transposon. Silencing of Zbed6 in mouse C2C12 myoblasts affected Igf2 expression, cell proliferation, wound healing, and myotube formation. Chromatin immunoprecipitation (Ch......, including development and transcriptional regulation. The phenotypic effects in mutant pigs and ZBED6-silenced C2C12 myoblasts, the extreme sequence conservation, its nucleolar localization, the broad tissue distribution, and the many target genes with essential biological functions suggest that ZBED6...... is an important transcription factor in placental mammals, affecting development, cell proliferation, and growth....

IGF-II Promotes Stemness of Neural Restricted Precursors

Science.gov (United States)

Ziegler, Amber N.; Schneider, Joel S.; Qin, Mei; Tyler, William A.; Pintar, John E.; Fraidenraich, Diego; Wood, Teresa L.; Levison, Steven W.

2016-01-01

Insulin-like growth factor (IGF)-I and IGF-II regulate brain development and growth through the IGF type 1 receptor (IGF-1R). Less appreciated is that IGF-II, but not IGF-I, activates a splice variant of the insulin receptor (IR) known as IR-A. We hypothesized that IGF-II exerts distinct effects from IGF-I on neural stem/progenitor cells (NSPs) via its interaction with IR-A. Immunofluorescence revealed high IGF-II in the medial region of the subventricular zone (SVZ) comprising the neural stem cell niche, with IGF-II mRNA predominant in the adjacent choroid plexus. The IGF-1R and the IR isoforms were differentially expressed with IR-A predominant in the medial SVZ, whereas the IGF-1R was more abundant laterally. Similarly, IR-A was more highly expressed by NSPs, whereas the IGF-1R was more highly expressed by lineage restricted cells. In vitro, IGF-II was more potent in promoting NSP expansion than either IGF-I or standard growth medium. Limiting dilution and differentiation assays revealed that IGF-II was superior to IGF-I in promoting stemness. In vivo, NSPs propagated in IGF-II migrated to and took up residence in periventricular niches while IGF-I-treated NSPs predominantly colonized white matter. Knockdown of IR or IGF-1R using shRNAs supported the conclusion that the IGF-1R promotes progenitor proliferation, whereas the IR is important for self-renewal. Q-PCR revealed that IGF-II increased Oct4, Sox1, and FABP7 mRNA levels in NSPs. Our data support the conclusion that IGF-II promotes the self-renewal of neural stem/progenitors via the IR. By contrast, IGF-1R functions as a mitogenic receptor to increase precursor abundance. PMID:22593020

HSF1 phosphorylation by ERK/GSK3 suppresses RNF126 to sustain IGF-IIR expression for hypertension-induced cardiomyocyte hypertrophy.

Science.gov (United States)

Huang, Chih-Yang; Lee, Fa-Lun; Peng, Shu-Fen; Lin, Kuan-Ho; Chen, Ray-Jade; Ho, Tsung-Jung; Tsai, Fu-Jen; Padma, Vijaya V; Kuo, Wei-Wen; Huang, Chih-Yang

2018-02-01

Hypertension-induced cardiac hypertrophy and apoptosis are major characteristics of early-stage heart failure (HF). Inhibition of extracellular signal-regulated kinases (ERK) efficaciously suppressed angiotensin II (ANG II)-induced cardiomyocyte hypertrophy and apoptosis by blocking insulin-like growth factor II receptor (IGF-IIR) signaling. However, the detailed mechanism by which ANG II induces ERK-mediated IGF-IIR signaling remains elusive. Here, we found that ANG II activated ERK to upregulate IGF-IIR expression via the angiotensin II type I receptor (AT 1 R). ERK activation subsequently phosphorylates HSF1 at serine 307, leading to a secondary phosphorylation by glycogen synthase kinase III (GSK3) at serine 303. Moreover, we found that ANG II mediated ERK/GSK3-induced IGF-IIR protein stability by downregulating the E3 ubiquitin ligase of IGF-IIR RING finger protein CXXVI (RNF126). The expression of RNF126 decreased following ANG II-induced HSF1 S303 phosphorylation, resulting in IGF-IIR protein stability and increased cardiomyocyte injury. Inhibition of GSK3 significantly alleviated ANG II-induced cardiac hypertrophy in vivo and in vitro. Taken together, these results suggest that HSF1 phosphorylation stabilizes IGF-IIR protein stability by downregulating RNF126 during cardiac hypertrophy. ANG II activates ERK/GSK3 to phosphorylate HSF1, resulting in RNF126 degradation, which stabilizes IGF-IIR protein expression and eventually results in cardiac hypertrophy. HSF1 could be a valuable therapeutic target for cardiac diseases among hypertensive patients. © 2017 Wiley Periodicals, Inc.

Human GH Receptor-IGF-1 Receptor Interaction: Implications for GH Signaling

Science.gov (United States)

Gan, Yujun; Buckels, Ashiya; Liu, Ying; Zhang, Yue; Paterson, Andrew J.; Jiang, Jing; Zinn, Kurt R.

2014-01-01

GH signaling yields multiple anabolic and metabolic effects. GH binds the transmembrane GH receptor (GHR) to activate the intracellular GHR-associated tyrosine kinase, Janus kinase 2 (JAK2), and downstream signals, including signal transducer and activator of transcription 5 (STAT5) activation and IGF-1 gene expression. Some GH effects are partly mediated by GH-induced IGF-1 via IGF-1 receptor (IGF-1R), a tyrosine kinase receptor. We previously demonstrated in non-human cells that GH causes formation of a GHR-JAK2-IGF-1R complex and that presence of IGF-1R (even without IGF-1 binding) augments proximal GH signaling. In this study, we use human LNCaP prostate cancer cells as a model system to further study the IGF-1R's role in GH signaling. GH promoted JAK2 and GHR tyrosine phosphorylation and STAT5 activation in LNCaP cells. By coimmunoprecipitation and a new split luciferase complementation assay, we find that GH augments GHR/IGF-1R complex formation, which is inhibited by a Fab of an antagonistic anti-GHR monoclonal antibody. Short hairpin RNA-mediated IGF-1R silencing in LNCaP cells reduced GH-induced GHR, JAK2, and STAT5 phosphorylation. Similarly, a soluble IGF-1R extracellular domain fragment (sol IGF-1R) interacts with GHR in response to GH and blunts GH signaling. Sol IGF-1R also markedly inhibits GH-induced IGF-1 gene expression in both LNCaP cells and mouse primary osteoblast cells. On the basis of these and other findings, we propose a model in which IGF-1R augments GH signaling by allowing a putative IGF-1R-associated molecule that regulates GH signaling to access the activated GHR/JAK2 complex and envision sol IGF-1R as a dominant-negative inhibitor of this IGF-1R-mediated augmentation. Physiological implications of this new model are discussed. PMID:25211187

The proto-oncogene product c-Crk associates with insulin receptor substrate-1 and 4PS. Modulation by insulin growth factor-I (IGF) and enhanced IGF-I signaling.

Science.gov (United States)

Beitner-Johnson, D; Blakesley, V A; Shen-Orr, Z; Jimenez, M; Stannard, B; Wang, L M; Pierce, J; LeRoith, D

1996-04-19

The Crk proto-oncogene product is an SH2 and SH3 domain-containing adaptor protein which we have previously shown to become rapidly tyrosine phosphorylated in response to stimulation with insulin-like growth factor I (IGF-I) in NIH-3T3 cells. In order to further characterize the role of Crk in the IGF-I signaling pathway, NIH-3T3 and 293 cells were stably transfected with an expression vector containing the Crk cDNA. The various resultant 3T3-Crk clones expressed Crk at approximately 2-15-fold higher levels than parental 3T3 cells. In 3T3-Crk cells, Crk immunoreactivity was detected in insulin receptor substrate-1 (IRS-1) immunoprecipitates. Stimulation with IGF-I resulted in a dissociation of Crk protein from IRS-1. In contrast, the association of the related adaptor protein Grb2 with IRS-1 was enhanced by IGF-I stimulation. Similar results were obtained in stably transfected 293-Crk cells, which express both IRS-1 and the IRS-1-related signaling protein 4PS. In these cells, IRS-1 and 4PS both associated with Crk, and this association was also decreased by IGF-I treatment, whereas the association of Grb2 with IRS-1 and 4PS was enhanced by IGF-I. Overexpression of Crk also enhanced IGF-I-induced mitogenesis of NIH-3T3 cells, as measured by [3H]thymidine incorporation. The levels of IGF-I-induced mitogenesis were proportional to the level of Crk expression. These results suggest that Crk is a positive effector of IGF-I signaling, and may mediate its effects via interaction with IRS-1 and/or 4PS.

β-Catenin/POU5F1/SOX2 transcription factor complex mediates IGF-I receptor signaling and predicts poor prognosis in lung adenocarcinoma.

Science.gov (United States)

Xu, Chuan; Xie, Dan; Yu, Shi-Cang; Yang, Xiao-Jun; He, Li-Ru; Yang, Jing; Ping, Yi-Fang; Wang, Bin; Yang, Lang; Xu, Sen-Lin; Cui, Wei; Wang, Qing-Liang; Fu, Wen-Juan; Liu, Qing; Qian, Cheng; Cui, You-Hong; Rich, Jeremy N; Kung, Hsiang-Fu; Zhang, Xia; Bian, Xiu-Wu

2013-05-15

Cancer stem-like cells (CSLC) are crucial in tumor initiation and progression; however, the underlying mechanism for the self-renewal of cancer cells remains undefined. In the study, immunohistochemical analysis of specimens freshly excised from patients with lung adenocarcinoma showed that high expression of insulin-like growth factor I receptor (IGF-IR) in lung adenocarcinoma cells was positively correlated with the expressions of cancer stem cell markers CD133 and aldehyde dehydrogenase 1 family member A1 (ALDH1A1). IGF-IR activation enhanced POU class 5 homeobox 1 (POU5F1) expression on human lung adenocarcinoma stem-like cells (LACSLC) through PI3K/AKT/GSK3β/β-catenin cascade. POU5F1 could form a novel complex with β-catenin and SOX2 to bind Nanog promoter for transcription to maintain self-renewal of LACSLCs, which was dependent on the functional IGF-IR. Genetic and pharmacologic inhibition of IGF-IR abrogated LACSLC capabilities for self-renewal and tumorigenicity in vitro. In an in vivo xenograft tumor model, knockdown of either IGF-IR or POU5F1 impeded tumorigenic potentials of LACSLCs. By analyzing pathologic specimens excised from 200 patients with lung adenocarcinoma, we found that colocalization of highly expressed IGF-IR with β-catenin and POU5F1 predicted poor prognosis. Taken together, we show that IGF-IR-mediated POU5F1 expression to form a complex with β-catenin and SOX2 is crucial for the self-renewal and oncogenic potentials of LACSLCs, and the integrative clinical detection of the expressions of IGF-IR, β-catenin, and POU5F1 is indicatory for predicting prognosis in the patients of lung adenocarcinoma. ©2013 AACR.

Insulin-like growth factor (IGF) binding protein from human decidua inhibits the binding and biological action of IGF-I in cultured choriocarcinoma cells

International Nuclear Information System (INIS)

Ritvos, O.; Ranta, T.; Jalkanen, J.; Suikkari, A.M.; Voutilainen, R.; Bohn, H.; Rutanen, E.M.

1988-01-01

The placenta expresses genes for insulin-like growth factors (IGFs) and possesses IGF-receptors, suggesting that placental growth is regulated by IGFs in an autocrine manner. We have previously shown that human decidua, but not placenta, synthesizes and secretes a 34 K IGF-binding protein (34 K IGF-BP) called placental protein 12. We now used human choriocarcinoma JEG-3 cell monolayer cultures and recombinant (Thr59)IGF-I as a model to study whether the decidual 34 K IGF-BP is able to modulate the receptor binding and biological activity of IGFs in trophoblasts. JEG-3 cells, which possess type I IGF receptors, were unable to produce IGF-BPs. Purified 34 K IGF-BP specifically bound [125I]iodo-(Thr59)IGF-I. Multiplication-stimulating activity had 2.5% the potency of (Thr59)IGF-I, and insulin had no effect on the binding of [125I] iodo-(Thr59)IGF-I. 34 K IGF-BP inhibited the binding of [125I] iodo-(Thr59)IGF-I to JEG-3 monolayers in a concentration-dependent manner by forming with the tracer a soluble complex that could not bind to the cell surface as demonstrated by competitive binding and cross-linking experiments. After incubating the cell monolayers with [125I]iodo-(Thr59)IGF-I in the presence of purified binding protein, followed by cross-linking, no affinity labeled bands were seen on autoradiography. In contrast, an intensely labeled band at 40 K was detected when the incubation medium was analyzed, suggesting that (Thr59)IGF-I and 34 K IGF-BP formed a complex in a 1:1 molar ratio. Also, 34 K IGF-BP inhibited both basal and IGF-I-stimulated uptake of alpha-[3H]aminoisobutyric acid in JEG-3 cells. RNA analysis revealed that IGF-II is expressed in JEG-3 cells

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker.

Science.gov (United States)

Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E; Whitley, Guy; Johnsen, Guro M; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C; Müller, Dominik N; Staff, Anne Cathrine; Hurst, Laurence D; Dechend, Ralf; Izsvák, Zsuzsanna

2017-11-07

Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5 , with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5 high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in

Studies on Expression of IGF-Ⅱ Gene in Deciduas De-rived from Medical Abortion Patients

Institute of Scientific and Technical Information of China (English)

刘峻; 汪玉宝; 毛叶萌; 毛全福; 杜晓岩

2000-01-01

Objective To determine the effect of insulin-like growth factor- Ⅱ (IGF- Ⅱ ) upon the maintenance of decidua in early pregnancy and its relationship with progesterone, as well as its role in medical abortion.Materials & Methods Decidua tissue was obtained from 28 women who undergoing surgical abortion and 39 for medical abortion respectively at 5～7 weeks of gestation.The extracted total RNA was reversely transeripted and amplified by PCR with spe-cific primers (IGF- Ⅱ and β-actin). The products were semi-quantitated by MIAS 300 system and qualitatively analyzed by southern blotting.Results The expression of IGF- Ⅱ gene in decidua from surgical abortion was signif-icantly higher than that from medical abortion (P<0. 05). The average IGF- Ⅱ gene transcription values were 1.54±0. 79 and 0. 72± 0. 39 respectively. The results of southern blotting proved qualitatively that the RT-PCR products were IGF- Ⅱ cDNA.Conclusion IGF- Ⅱ plays a role in the maintenance of decidua in early pregnancy. It may act as a mediator of progestin. It's also involved in the molecular mechanism of mifepristone.

IGF binding proteins.

Science.gov (United States)

Bach, Leon A

2017-12-18

Insulin-like growth factor binding proteins (IGFBPs) 1-6 bind IGFs but not insulin with high affinity. They were initially identified as serum carriers and passive inhibitors of IGF actions. However, subsequent studies showed that, although IGFBPs inhibit IGF actions in many circumstances, they may also potentiate these actions. IGFBPs are widely expressed in most tissues, and they are flexible endocrine and autocrine/paracrine regulators of IGF activity, which is essential for this important physiological system. More recently, individual IGFBPs have been shown to have IGF-independent actions. Mechanisms underlying these actions include (i) interaction with non-IGF proteins in compartments including the extracellular space and matrix, the cell surface and intracellularly; (ii) interaction with and modulation of other growth factor pathways including EGF, TGF- and VEGF; and (iii) direct or indirect transcriptional effects following nuclear entry of IGFBPs. Through these IGF-dependent and IGF-independent actions, IGFBPs modulate essential cellular processes including proliferation, survival, migration, senescence, autophagy and angiogenesis. They have been implicated in a range of disorders including malignant, metabolic, neurological and immune diseases. A more complete understanding of their cellular roles may lead to the development of novel IGFBP-based therapeutic opportunities.

R1507, an Anti-Insulin-Like Growth Factor-1 Receptor (IGF-1R) Antibody, and EWS/FLI-1 siRNA in Ewing's Sarcoma: Convergence at the IGF/IGFR/Akt Axis

Science.gov (United States)

Rodon, Jordi; Sun, Michael; Kuenkele, Klaus-Peter; Parsons, Henrique A.; Trent, Jonathan C.; Kurzrock, Razelle

2011-01-01

A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R) antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si) RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71) was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays). TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney) cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt. PMID:22022506

R1507, an anti-insulin-like growth factor-1 receptor (IGF-1R antibody, and EWS/FLI-1 siRNA in Ewing's sarcoma: convergence at the IGF/IGFR/Akt axis.

Directory of Open Access Journals (Sweden)

Helen J Huang

Full Text Available A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71 was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays. TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt.

Role of IGF1R in breast cancer subtypes, stemness, and lineage differentiation

Directory of Open Access Journals (Sweden)

Susan M Farabaugh

2015-04-01

Full Text Available Insulin-like growth factor (IGF signaling is fundamental for growth and survival. A large body of evidence (laboratory, epidemiological, and clinical implicates the exploitation of this pathway in cancer. Up to 50% of breast tumors express the activated form of the IGF1 receptor (IGF1R. Breast cancers are categorized into subtypes based upon hormone and ERRB2 receptor expression and/or gene expression profiling. Even though IGF1R influences tumorigenic phenotypes and drug resistance across all breast cancer subtypes, it has specific expression and function in each. In some subtypes, IGF1R levels correlate with a favorable prognosis, while in others it is associated with recurrence and poor prognosis, suggesting different actions based upon cellular and molecular contexts. In this review, we examine IGF1R expression and function as it relates to breast cancer subtype and therapy-acquired resistance. Additionally, we discuss the role of IGF1R in stem cell maintenance and lineage differentiation and how these cell fate influences may alter the differentiation potential and cellular composition of breast tumors.

Methylation and Transcripts Expression at the Imprinted GNAS Locus in Human Embryonic and Induced Pluripotent Stem Cells and Their Derivatives

Directory of Open Access Journals (Sweden)

Virginie Grybek

2014-09-01

Full Text Available Data from the literature indicate that genomic imprint marks are disturbed in human pluripotent stem cells (PSCs. GNAS is an imprinted locus that produces one biallelic (Gsα and four monoallelic (NESP55, GNAS-AS1, XLsα, and A/B transcripts due to differential methylation of their promoters (DMR. To document imprinting at the GNAS locus in PSCs, we studied GNAS locus DMR methylation and transcript (NESP55, XLsα, and A/B expression in human embryonic stem cells (hESCs and human induced pluripotent stem cells (hiPSCs derived from two human fibroblasts and their progenies. Results showed that (1 methylation at the GNAS locus DMRs is DMR and cell line specific, (2 changes in allelic transcript expression can be independent of a change in allele-specific DNA methylation, and (3 interestingly, methylation at A/B DMR is correlated with A/B transcript expression. These results indicate that these models are valuable to study the mechanisms controlling GNAS methylation, factors involved in transcript expression, and possibly mechanisms involved in the pathophysiology of pseudohypoparathyroidism type 1B.

Locally expressed IGF1 propeptide improves mouse heart function in induced dilated cardiomyopathy by blocking myocardial fibrosis and SRF-dependent CTGF induction

Directory of Open Access Journals (Sweden)

Melissa Touvron

2012-07-01

Cardiac fibrosis is critically involved in the adverse remodeling accompanying dilated cardiomyopathies (DCMs, which leads to cardiac dysfunction and heart failure (HF. Connective tissue growth factor (CTGF, a profibrotic cytokine, plays a key role in this deleterious process. Some beneficial effects of IGF1 on cardiomyopathy have been described, but its potential role in improving DCM is less well characterized. We investigated the consequences of expressing a cardiac-specific transgene encoding locally acting IGF1 propeptide (muscle-produced IGF1; mIGF1 on disease progression in a mouse model of DCM [cardiac-specific and inducible serum response factor (SRF gene disruption] that mimics some forms of human DCM. Cardiac-specific mIGF1 expression substantially extended the lifespan of SRF mutant mice, markedly improved cardiac functions, and delayed both DCM and HF. These protective effects were accompanied by an overall improvement in cardiomyocyte architecture and a massive reduction of myocardial fibrosis with a concomitant amelioration of inflammation. At least some of the beneficial effects of mIGF1 transgene expression were due to mIGF1 counteracting the strong increase in CTGF expression within cardiomyocytes caused by SRF deficiency, resulting in the blockade of fibroblast proliferation and related myocardial fibrosis. These findings demonstrate that SRF plays a key role in the modulation of cardiac fibrosis through repression of cardiomyocyte CTGF expression in a paracrine fashion. They also explain how impaired SRF function observed in human HF promotes fibrosis and adverse cardiac remodeling. Locally acting mIGF1 efficiently protects the myocardium from these adverse processes, and might thus represent a therapeutic avenue to counter DCM.

mRNA levels of imprinted genes in bovine in vivo oocytes, embryos and cross species comparisons in humans, mice and pigs

Science.gov (United States)

Twenty-six confirmed imprinted genes in the bovine were quantified in in vivo produced oocytes and embryos. Eighteen were detectable and their transcriptional abundance were categorized into five patterns: largely decreased (MEST and PLAGL1); first decreased and then increased (CDKN1C and IGF2R); p...

IGF-1R Promotes Symmetric Self-Renewal and Migration of Alkaline Phosphatase+ Germ Stem Cells through HIF-2α-OCT4/CXCR4 Loop under Hypoxia

Directory of Open Access Journals (Sweden)

Yung-Che Kuo

2018-02-01

Full Text Available Summary: Hypoxia cooperates with endocrine signaling to maintain the symmetric self-renewal proliferation and migration of embryonic germline stem cells (GSCs. However, the lack of an appropriate in vitro cell model has dramatically hindered the understanding of the mechanism underlying this cooperation. Here, using a serum-free system, we demonstrated that hypoxia significantly induced the GSC mesenchymal transition, increased the expression levels of the pluripotent transcription factor OCT4 and migration-associated proteins (SDF-1, CXCR4, IGF-1, and IGF-1R, and activated the cellular expression and translocalization of the CXCR4-downstream proteins ARP3/pFAK. The underlying mechanism involved significant IGF-1/IGF-1R activation of OCT4/CXCR4 expression through HIF-2α regulation. Picropodophyllin-induced inhibition of IGF-1R phosphorylation significantly suppressed hypoxia-induced SDF-1/CXCR4 expression and cell migration. Furthermore, transactivation between IGF-1R and CXCR4 was involved. In summary, we demonstrated that niche hypoxia synergistically cooperates with its associated IGF-1R signaling to regulate the symmetric division (self-renewal proliferation and cell migration of alkaline phosphatase-positive GSCs through HIF-2α-OCT4/CXCR4 during embryogenesis. : In this article, Huang and colleagues demonstrate that niche hypoxia promotes symmetric self-renewal proliferation and migration of PGC-like CD49f+AP+GSCs through IGF-IR regulation. Using a serum-free culture system, the crosstalk between IGF-1R and CXCR4 signaling was discovered. This work demonstrated that embryonic hypoxia synergistically cooperated with IGF-1R signaling to regulate the symmetric self-renewal and migration of PGC-like GSCs through a HIF-2α–OCT4/CXCR4 loop. Keywords: hypoxia, niche, germline stem cells, self-renewal, migration, IGF-1R, HIF-2α, OCT4, SDF-1, CXCR4

IGF-1 prevents simvastatin-induced myotoxicity in C2C12 myotubes.

Science.gov (United States)

Bonifacio, Annalisa; Sanvee, Gerda M; Brecht, Karin; Kratschmar, Denise V; Odermatt, Alex; Bouitbir, Jamal; Krähenbühl, Stephan

2017-05-01

Statins are generally well tolerated, but treatment with these drugs may be associated with myopathy. The mechanisms of statin-associated myopathy are not completely understood. Statins inhibit AKT phosphorylation by an unclear mechanism, whereas insulin-like growth factor (IGF-1) activates the IGF-1/AKT signaling pathway and promotes muscle growth. The aims of the study were to investigate mechanisms of impaired AKT phosphorylation by simvastatin and to assess effects of IGF-1 on simvastatin-induced myotoxicity in C2C12 myotubes. C2C12 mouse myotubes were exposed to 10 μM simvastatin and/or 10 ng/mL IGF-1 for 18 h. Simvastatin inhibited the IGF-1/AKT signaling pathway, resulting in increased breakdown of myofibrillar proteins, impaired protein synthesis and increased apoptosis. Simvastatin inhibited AKT S473 phosphorylation, indicating reduced activity of mTORC2. In addition, simvastatin impaired stimulation of AKT T308 phosphorylation by IGF-1, indicating reduced activation of the IGF-1R/PI3K pathway by IGF-1. Nevertheless, simvastatin-induced myotoxicity could be at least partially prevented by IGF-1. The protective effects of IGF-1 were mediated by activation of the IGF-1R/AKT signaling cascade. Treatment with IGF-1 also suppressed muscle atrophy markers, restored protein synthesis and inhibited apoptosis. These results were confirmed by normalization of myotube morphology and protein content of C2C12 cells exposed to simvastatin and treated with IGF-1. In conclusion, impaired activity of AKT can be explained by reduced function of mTORC2 and of the IGF-1R/PI3K pathway. IGF-1 can prevent simvastatin-associated cytotoxicity and metabolic effects on C2C12 cells. The study gives insight into mechanisms of simvastatin-associated myotoxicity and provides potential targets for therapeutic intervention.

Regulation of hypoxia-inducible factor-1α (HIF-1α expression by interleukin-1β (IL-1 β, insulin-like growth factors I (IGF-I and II (IGF-II in human osteoarthritic chondrocytes

Directory of Open Access Journals (Sweden)

Angelica Rossi Sartori-Cintra

2012-01-01

Full Text Available OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α can regulate cytokines (catabolic action and/or growth factors (anabolic action in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β and insulin-like growth factors I (IGF-I and II (IGF-II and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

International Nuclear Information System (INIS)

Zuloaga, R.; Fuentes, E.N.; Molina, A.; Valdés, J.A.

2013-01-01

Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP 3 /calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1 during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation

The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

Energy Technology Data Exchange (ETDEWEB)

Zuloaga, R. [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Fuentes, E.N.; Molina, A. [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción (Chile); Valdés, J.A., E-mail: jvaldes@unab.cl [Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago (Chile); Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción (Chile)

2013-10-18

Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP{sub 3}/calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1 during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation.

ZFP57 maintains the parent-of-origin-specific expression of the imprinted genes and differentially affects non-imprinted targets in mouse embryonic stem cells

DEFF Research Database (Denmark)

Riso, Vincenzo; Cammisa, Marco; Kukreja, Harpreet

2016-01-01

ZFP57 is necessary for maintaining repressive epigenetic modifications at Imprinting control regions (ICRs). In mouse embryonic stem cells (ESCs), ZFP57 binds ICRs (ICRBS) and many other loci (non-ICRBS). To address the role of ZFP57 on all its target sites, we performed high-throughput and multi......-locus analyses of inbred and hybrid mouse ESC lines carrying different gene knockouts. By using an allele-specific RNA-seq approach, we demonstrate that ZFP57 loss results in derepression of the imprinted allele of multiple genes in the imprinted clusters. We also find marked epigenetic differences between ICRBS...... the imprinted expression over long distances. At non-ICRBS, ZFP57 inactivation results in acquisition of epigenetic features that are characteristic of poised enhancers, suggesting that another function of ZFP57 in early embryogenesis is to repress cis-acting regulatory elements whose activity is not yet...

Impaired IGF1R signaling in cells expressing longevity-associated human IGF1R alleles

OpenAIRE

Tazearslan, Cagdas; Huang, Jing; Barzilai, Nir; Suh, Yousin

2011-01-01

Dampening of insulin/insulin like growth factor-1 (IGF1) signaling results in extension of lifespan in invertebrate as well as murine models. The impact of this evolutionarily conserved pathway on modulation of human lifespan remains unclear. We previously identified two IGF1R mutations (Ala-37-Thr and Arg-407-His) that are enriched in Ashkenazi Jewish centenarians as compared to younger controls and are associated with reduced activity of the IGF1 receptor as measured in immortalized lymphoc...

The Drosophila homolog of the mammalian imprint regulator, CTCF, maintains the maternal genomic imprint in Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Rasheva Vanya

2010-07-01

Full Text Available Abstract Background CTCF is a versatile zinc finger DNA-binding protein that functions as a highly conserved epigenetic transcriptional regulator. CTCF is known to act as a chromosomal insulator, bind promoter regions, and facilitate long-range chromatin interactions. In mammals, CTCF is active in the regulatory regions of some genes that exhibit genomic imprinting, acting as insulator on only one parental allele to facilitate parent-specific expression. In Drosophila, CTCF acts as a chromatin insulator and is thought to be actively involved in the global organization of the genome. Results To determine whether CTCF regulates imprinting in Drosophila, we generated CTCF mutant alleles and assayed gene expression from the imprinted Dp(1;fLJ9 mini-X chromosome in the presence of reduced CTCF expression. We observed disruption of the maternal imprint when CTCF levels were reduced, but no effect was observed on the paternal imprint. The effect was restricted to maintenance of the imprint and was specific for the Dp(1;fLJ9 mini-X chromosome. Conclusions CTCF in Drosophila functions in maintaining parent-specific expression from an imprinted domain as it does in mammals. We propose that Drosophila CTCF maintains an insulator boundary on the maternal X chromosome, shielding genes from the imprint-induced silencing that occurs on the paternally inherited X chromosome. See commentary: http://www.biomedcentral.com/1741-7007/8/104

IGF-I and IGFBP2 in peripheral artery disease

DEFF Research Database (Denmark)

Urbonaviciene, Grazina; Frystyk, Jan; Urbonavicius, Sigitas

2014-01-01

BACKGROUND AND OBJECTIVES: The search for novel risk factors of cardiovascular disease (CVD) has provided valuable clinical data concerning underlying mechanism of disease. Increasing evidence indicates a possible involvement of insulin-like growth factor-I (IGF-I) and its binding protein 2 (IGFBP......-2) in the pathogenesis of CVD disorders. The aim of this study was to examine the relationship between levels of IGF-I and IGFBP-2 with all-cause and CVD mortality in a prospective study of patients with lower-extremity peripheral artery disease (PAD). METHODS AND MATERIAL: Serum IGF-I and IGFBP-2...... levels were obtained in 440 patients (257 males) with symptomatic PAD. Patients were followed for a median of 6.1 (IQ 5.1-7.2) years. The relationship between times to lethal outcome and baseline serum IGF-I and IFGBP-2 levels were examined by Cox proportional hazard analysis. The role of IFGBP-2...

Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9

Energy Technology Data Exchange (ETDEWEB)

Deng, Hua; Lin, Yingbo; Badin, Margherita; Vasilcanu, Daiana; Stroemberg, Thomas [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden); Jernberg-Wiklund, Helena [Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala (Sweden); Sehat, Bita [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden); Larsson, Olle, E-mail: olle.larsson@ki.se [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden)

2011-01-14

Research highlights: {yields} SUMOylation mediates nuclear translocation of IGF-1R which activates transcription. {yields} Here we show that nuclear IGF-1R over-accumulates in tumor cells. {yields} This requires overexpression of the receptor that is a common feature in tumor cells. {yields} An increased expression of the SUMO ligase Ubc9 seems to be an involved mechanism too. -- Abstract: The insulin-like growth factor 1 receptor (IGF-1R) plays crucial roles in tumor cell growth and is overexpressed in many cancers. IGF-1R's trans-membrane kinase signaling pathways have been well characterized. Very recently, we showed that SUMOylation mediates nuclear translocation of the IGF-1R, and that nuclear IGF-1R (nIGF-1R) binds to enhancer regions and activates transcription. We identified three lysine residues in the {beta}-subunit of the receptor and that mutation of these blocks nuclear translocation and gene activation. Furthermore, accumulation of nIGF-1R was proven strongly dependent on the specific SUMO-conjugating enzyme Ubc9. Here we show that nIGF-1R originates solely from the cell membrane and that phosphorylation of the core tyrosine residues of the receptor kinase is crucial for nuclear accumulation. We also compared the levels of nIGF-1R, measured as nuclear/membrane ratios, in tumor and normal cells. We found that the breast cancer cell line MCF-7 has 13-fold higher amounts of nIGF-1R than breast epithelial cells (IME) which showed only a small amount of nIGF-1R. In comparison, the total expression of IGF-1R was only 3.7- higher in MCF-7. Comparison of several other tumor and normal cell lines showed similar tumor cell over-accumulation of nIGF-1R, exceeding the total receptor expression substantially. Ectopic overexpression (>10-fold) of the receptor increased nIGF-1R in IME cells but not to that high level as in wild type MCF-7. The levels of Ubc9 were higher in all tumor cell lines, compared to the normal cells, and this probably contributes to over

Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9

International Nuclear Information System (INIS)

Deng, Hua; Lin, Yingbo; Badin, Margherita; Vasilcanu, Daiana; Stroemberg, Thomas; Jernberg-Wiklund, Helena; Sehat, Bita; Larsson, Olle

2011-01-01

Research highlights: → SUMOylation mediates nuclear translocation of IGF-1R which activates transcription. → Here we show that nuclear IGF-1R over-accumulates in tumor cells. → This requires overexpression of the receptor that is a common feature in tumor cells. → An increased expression of the SUMO ligase Ubc9 seems to be an involved mechanism too. -- Abstract: The insulin-like growth factor 1 receptor (IGF-1R) plays crucial roles in tumor cell growth and is overexpressed in many cancers. IGF-1R's trans-membrane kinase signaling pathways have been well characterized. Very recently, we showed that SUMOylation mediates nuclear translocation of the IGF-1R, and that nuclear IGF-1R (nIGF-1R) binds to enhancer regions and activates transcription. We identified three lysine residues in the β-subunit of the receptor and that mutation of these blocks nuclear translocation and gene activation. Furthermore, accumulation of nIGF-1R was proven strongly dependent on the specific SUMO-conjugating enzyme Ubc9. Here we show that nIGF-1R originates solely from the cell membrane and that phosphorylation of the core tyrosine residues of the receptor kinase is crucial for nuclear accumulation. We also compared the levels of nIGF-1R, measured as nuclear/membrane ratios, in tumor and normal cells. We found that the breast cancer cell line MCF-7 has 13-fold higher amounts of nIGF-1R than breast epithelial cells (IME) which showed only a small amount of nIGF-1R. In comparison, the total expression of IGF-1R was only 3.7- higher in MCF-7. Comparison of several other tumor and normal cell lines showed similar tumor cell over-accumulation of nIGF-1R, exceeding the total receptor expression substantially. Ectopic overexpression (>10-fold) of the receptor increased nIGF-1R in IME cells but not to that high level as in wild type MCF-7. The levels of Ubc9 were higher in all tumor cell lines, compared to the normal cells, and this probably contributes to over-accumulation of nIGF-1R

Phosphatidylinositol 3-Kinase (PI3K) Activity Bound to Insulin-like Growth Factor-I (IGF-I) Receptor, which Is Continuously Sustained by IGF-I Stimulation, Is Required for IGF-I-induced Cell Proliferation*

Science.gov (United States)

Fukushima, Toshiaki; Nakamura, Yusaku; Yamanaka, Daisuke; Shibano, Takashi; Chida, Kazuhiro; Minami, Shiro; Asano, Tomoichiro; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

2012-01-01

Continuous stimulation of cells with insulin-like growth factors (IGFs) in G1 phase is a well established requirement for IGF-induced cell proliferation; however, the molecular components of this prolonged signaling pathway that is essential for cell cycle progression from G1 to S phase are unclear. IGF-I activates IGF-I receptor (IGF-IR) tyrosine kinase, followed by phosphorylation of substrates such as insulin receptor substrates (IRS) leading to binding of signaling molecules containing SH2 domains, including phosphatidylinositol 3-kinase (PI3K) to IRS and activation of the downstream signaling pathways. In this study, we found prolonged (>9 h) association of PI3K with IGF-IR induced by IGF-I stimulation. PI3K activity was present in this complex in thyrocytes and fibroblasts, although tyrosine phosphorylation of IRS was not yet evident after 9 h of IGF-I stimulation. IGF-I withdrawal in mid-G1 phase impaired the association of PI3K with IGF-IR and suppressed DNA synthesis the same as when PI3K inhibitor was added. Furthermore, we demonstrated that Tyr1316-X-X-Met of IGF-IR functioned as a PI3K binding sequence when this tyrosine is phosphorylated. We then analyzed IGF signaling and proliferation of IGF-IR−/− fibroblasts expressing exogenous mutant IGF-IR in which Tyr1316 was substituted with Phe (Y1316F). In these cells, IGF-I stimulation induced tyrosine phosphorylation of IGF-IR and IRS-1/2, but mutated IGF-IR failed to bind PI3K and to induce maximal phosphorylation of GSK3β and cell proliferation in response to IGF-I. Based on these results, we concluded that PI3K activity bound to IGF-IR, which is continuously sustained by IGF-I stimulation, is required for IGF-I-induced cell proliferation. PMID:22767591

Sexual dimorphism in parental imprint ontogeny and contribution to embryonic development.

Science.gov (United States)

Bourc'his, Déborah; Proudhon, Charlotte

2008-01-30

Genomic imprinting refers to the functional non-equivalence of parental genomes in mammals that results from the parent-of-origin allelic expression of a subset of genes. Parent-specific expression is dependent on the germ line acquisition of DNA methylation marks at imprinting control regions (ICRs), coordinated by the DNA-methyltransferase homolog DNMT3L. We discuss here how the gender-specific stages of DNMT3L expression may have influenced the various sexually dimorphic aspects of genomic imprinting: (1) the differential developmental timing of methylation establishment at paternally and maternally imprinted genes in each parental germ line, (2) the differential dependence on DNMT3L of parental methylation imprint establishment, (3) the unequal duration of paternal versus maternal methylation imprints during germ cell development, (4) the biased distribution of methylation-dependent ICRs towards the maternal genome, (5) the different genomic organization of paternal versus maternal ICRs, and finally (6) the overwhelming contribution of maternal germ line imprints to development compared to their paternal counterparts.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins.

Science.gov (United States)

González-Guerra, José Luis; Castilla-Cortazar, Inma; Aguirre, Gabriel A; Muñoz, Úrsula; Martín-Estal, Irene; Ávila-Gallego, Elena; Granado, Miriam; Puche, Juan E; García-Villalón, Ángel Luis

2017-01-01

Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins.

Directory of Open Access Journals (Sweden)

José Luis González-Guerra

Full Text Available Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R. In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides; carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.

Enhanced contractile force generation by artificial skeletal muscle tissues using IGF-I gene-engineered myoblast cells.

Science.gov (United States)

Sato, Masanori; Ito, Akira; Kawabe, Yoshinori; Nagamori, Eiji; Kamihira, Masamichi

2011-09-01

The aim of this study was to investigate whether insulin-like growth factor (IGF)-I gene delivery to myoblast cells promotes the contractile force generated by hydrogel-based tissue-engineered skeletal muscles in vitro. Two retroviral vectors allowing doxycycline (Dox)-inducible expression of the IGF-I gene were transduced into mouse myoblast C2C12 cells to evaluate the effects of IGF-I gene expression on these cells. IGF-I gene expression stimulated the proliferation of C2C12 cells, and a significant increase in the growth rate was observed for IGF-I-transduced C2C12 cells with Dox addition, designated C2C12/IGF (Dox+) cells. Quantitative morphometric analyses showed that the myotubes induced from C2C12/IGF (Dox+) cells had a larger area and a greater width than control myotubes induced from normal C2C12 cells. Artificial skeletal muscle tissues were prepared from the respective cells using hydrogels composed of type I collagen and Matrigel. Western blot analyses revealed that the C2C12/IGF (Dox+) tissue constructs showed activation of a skeletal muscle hypertrophy marker (Akt) and enhanced expression of muscle-specific markers (myogenin, myosin heavy chain and tropomyosin). Moreover, the creatine kinase activity was increased in the C2C12/IGF (Dox+) tissue constructs. The C2C12/IGF (Dox+) tissue constructs contracted in response to electrical pulses, and generated a significantly higher physical force than the control C2C12 tissue constructs. These findings indicate that IGF-I gene transfer has the potential to yield functional skeletal muscle substitutes that are capable of in vivo restoration of the load-bearing function of injured muscle or acting as in vitro electrically-controlled bio-actuators. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Genomic Imprinting Was Evolutionarily Conserved during Wheat Polyploidization.

Science.gov (United States)

Yang, Guanghui; Liu, Zhenshan; Gao, Lulu; Yu, Kuohai; Feng, Man; Yao, Yingyin; Peng, Huiru; Hu, Zhaorong; Sun, Qixin; Ni, Zhongfu; Xin, Mingming

2018-01-01

Genomic imprinting is an epigenetic phenomenon that causes genes to be differentially expressed depending on their parent of origin. To evaluate the evolutionary conservation of genomic imprinting and the effects of ploidy on this process, we investigated parent-of-origin-specific gene expression patterns in the endosperm of diploid ( Aegilops spp), tetraploid, and hexaploid wheat ( Triticum spp) at various stages of development via high-throughput transcriptome sequencing. We identified 91, 135, and 146 maternally or paternally expressed genes (MEGs or PEGs, respectively) in diploid, tetraploid, and hexaploid wheat, respectively, 52.7% of which exhibited dynamic expression patterns at different developmental stages. Gene Ontology enrichment analysis suggested that MEGs and PEGs were involved in metabolic processes and DNA-dependent transcription, respectively. Nearly half of the imprinted genes exhibited conserved expression patterns during wheat hexaploidization. In addition, 40% of the homoeolog pairs originating from whole-genome duplication were consistently maternally or paternally biased in the different subgenomes of hexaploid wheat. Furthermore, imprinted expression was found for 41.2% and 50.0% of homolog pairs that evolved by tandem duplication after genome duplication in tetraploid and hexaploid wheat, respectively. These results suggest that genomic imprinting was evolutionarily conserved between closely related Triticum and Aegilops species and in the face of polyploid hybridization between species in these genera. © 2018 American Society of Plant Biologists. All rights reserved.

Expressão do mRNA para IGF-2 em oócitos e células do cumulus extraídos de folículos antrais e pré-antrais de ovelhas nativas do Estado de Pernambuco

Directory of Open Access Journals (Sweden)

Arthur N. Melo

Full Text Available RESUMO: Objetivou-se avaliar a expressão do mRNA para o gene do fator de crescimento IGF-2 em oócitos e células do cumulus de ovelhas em diferentes estágios do desenvolvimento folicular. Os folículos classificados morfologicamente como antrais (terciários e pré-ovulatórios foram aspirados manualmente para obtenção dos oócitos e células do cumulus. Os folículos pré-antrais (secundários foram extraídos do córtex ovariano, por microdissecção, e os oócitos retirados. Nos dois grupos, os oócitos foram desnudados e agrupados em “pools” de dez células cada (Grupo A, n=10; Grupo B, n=10 e dez amostras com grupos de células do cumulus (Grupo A1, n=10, B1, n=10. O mRNA foi extraído e convertido em cDNA utilizando a técnica da RT-PCR, utilizando Oligo DT randômico para o mRNA. A análise da expressão confirmou a expressão gênica para IGF-2 nos grupos de oócitos e células do cumulus. Houve um aumento da expressão relativa do mRNA para IGF-2 nos grupos de oócitos durante a fase mais tardia do desenvolvimento folicular e as diferenças foram consideradas significantes (p<0,05. Não houve variação significante da expressão de IGF2 entre os grupos de células do cumulus. Conclui-se que o fator de crescimento IGF-2 tem níveis mais elevados de expressão em oócitos ovinos, na segunda fase do desenvolvimento folicular, mas expressão semelhante em células do cumulus durante as fases estudadas do desenvolvimento folicular.

GH and IGF-I levels are positively associated with musculotendinous collagen expression: Experiments in acromegalic and GHD patients

DEFF Research Database (Denmark)

Doessing, Simon; Holm, Lars; Heinemeier, Katja

2010-01-01

OBJECTIVE: Disproportionate growth of musculoskeletal tissue is a major cause of morbidity in both acromegalic (ACRO) and GH-deficient (GHD) patients. GH/IGF1 is likely to play an important role in the regulation of tendon and muscle collagen. We hypothesized that the local production of collagen...... is associated with the level of GH/IGF1.DESIGN AND METHODS: As primary outcomes, collagen mRNA expression and collagen protein fractional synthesis rate (FSR) were determined locally in skeletal muscle and tendon in nine ACRO and nine GHD patients. Moreover, muscle myofibrillar protein synthesis and tendon...... collagen morphology were determined.RESULTS AND CONCLUSIONS: Muscle collagen I and III mRNA expression was higher in ACRO patients versus GHD patients (PIGF1Ea and IGF1Ec...

IGF-1R Promotes Symmetric Self-Renewal and Migration of Alkaline Phosphatase+ Germ Stem Cells through HIF-2α-OCT4/CXCR4 Loop under Hypoxia.

Science.gov (United States)

Kuo, Yung-Che; Au, Heng-Kien; Hsu, Jue-Liang; Wang, Hsiao-Feng; Lee, Chiung-Ju; Peng, Syue-Wei; Lai, Ssu-Chuan; Wu, Yu-Chih; Ho, Hong-Nerng; Huang, Yen-Hua

2018-02-13

Hypoxia cooperates with endocrine signaling to maintain the symmetric self-renewal proliferation and migration of embryonic germline stem cells (GSCs). However, the lack of an appropriate in vitro cell model has dramatically hindered the understanding of the mechanism underlying this cooperation. Here, using a serum-free system, we demonstrated that hypoxia significantly induced the GSC mesenchymal transition, increased the expression levels of the pluripotent transcription factor OCT4 and migration-associated proteins (SDF-1, CXCR4, IGF-1, and IGF-1R), and activated the cellular expression and translocalization of the CXCR4-downstream proteins ARP3/pFAK. The underlying mechanism involved significant IGF-1/IGF-1R activation of OCT4/CXCR4 expression through HIF-2α regulation. Picropodophyllin-induced inhibition of IGF-1R phosphorylation significantly suppressed hypoxia-induced SDF-1/CXCR4 expression and cell migration. Furthermore, transactivation between IGF-1R and CXCR4 was involved. In summary, we demonstrated that niche hypoxia synergistically cooperates with its associated IGF-1R signaling to regulate the symmetric division (self-renewal proliferation) and cell migration of alkaline phosphatase-positive GSCs through HIF-2α-OCT4/CXCR4 during embryogenesis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Fetal growth restriction and the programming of heart growth and cardiac insulin-like growth factor 2 expression in the lamb.

Science.gov (United States)

Wang, Kimberley C W; Zhang, Lei; McMillen, I Caroline; Botting, Kimberley J; Duffield, Jaime A; Zhang, Song; Suter, Catherine M; Brooks, Doug A; Morrison, Janna L

2011-10-01

Reduced growth in fetal life together with accelerated growth in childhood, results in a ~50% greater risk of coronary heart disease in adult life. It is unclear why changes in patterns of body and heart growth in early life can lead to an increased risk of cardiovascular disease in adulthood. We aimed to investigate the role of the insulin-like growth factors in heart growth in the growth-restricted fetus and lamb. Hearts were collected from control and placentally restricted (PR) fetuses at 137-144 days gestation and from average (ABW) and low (LBW) birth weight lambs at 21 days of age. We quantified cardiac mRNA expression of IGF-1, IGF-2 and their receptors, IGF-1R and IGF-2R, using real-time RT-PCR and protein expression of IGF-1R and IGF-2R using Western blotting. Combined bisulphite restriction analysis was used to assess DNA methylation in the differentially methylated region (DMR) of the IGF-2/H19 locus and of the IGF-2R gene. In PR fetal sheep, IGF-2, IGF-1R and IGF-2R mRNA expression was increased in the heart compared to controls. LBW lambs had a greater left ventricle weight relative to body weight as well as increased IGF-2 and IGF-2R mRNA expression in the heart, when compared to ABW lambs. No changes in the percentage of methylation of the DMRs of IGF-2/H19 or IGF-2R were found between PR and LBW when compared to their respective controls. In conclusion, a programmed increased in cardiac gene expression of IGF-2 and IGF-2R may represent an adaptive response to reduced substrate supply (e.g. glucose and/or oxygen) in order to maintain heart growth and may be the underlying cause for increased ventricular hypertrophy and the associated susceptibility of cardiomyocytes to ischaemic damage later in life.

Astragalus Extract Mixture HT042 Increases Longitudinal Bone Growth Rate by Upregulating Circulatory IGF-1 in Rats

Directory of Open Access Journals (Sweden)

Donghun Lee

2017-01-01

Full Text Available Astragalus extract mixture HT042 is a standardized ingredient of health functional food approved by Korean FDA with a claim of “height growth of children.” HT042 stimulates bone growth rate and increases local IGF-1 expression in growth plate of rats which can be considered as direct stimulation of GH and its paracrine/autocrine actions. However, it remains unclear whether HT042 stimulates circulatory IGF-1 which also plays a major role to stimulate bone growth. To determine the effects on circulatory IGF-1, IGF-1 and IGFBP-3 expressions and phosphorylation of JAK2/STAT5 were evaluated in the liver after 10 days of HT042 administration. HT042 upregulated liver IGF-1 and IGFBP-3 mRNA expression, IGF-1 protein expression, and phosphorylation of JAK2/STAT5. HT042 also increased bone growth rate and proliferative zonal height in growth plate. In conclusion, HT042 stimulates bone growth rate via increment of proliferative rate by upregulation of liver IGF-1 and IGFBP-3 mRNA followed by IGF-1 protein expression through phosphorylation of JAK2/STAT5, which can be regarded as normal functioning of GH-dependent endocrine pathway.

Investigation on the role of IGF-1 signal transduction in the biological radiation responses

Energy Technology Data Exchange (ETDEWEB)

Jung, U Hee; Jo, Sung Kee; Park, Hae Ran; Oh, Soo Jin; Cho, Eun Hee; Eom, Hyun Soo; Ju, Eun Jin

2009-05-15

Effects of {gamma}-irradiation on the IGF-1 related gene expressions and activations in various cell lines - Various expression patterns of IGF-1 and IGF-1R following {gamma}-irradiation were observed according to the cell lines - The increased expressions of IGF-1 and IGF-1R were observed in Balb/3T3 and NIH/3T3 cells - Among the IGF-1 downstream signaling molecules, the phosphorylated ERK5 were not changed by {gamma}-irradiation in all three examined cell lines, whereas the phosphorylated p65 were increased by {gamma} -irradiation in all cell lines. The role of IGF-1 and p38 signaling in {gamma}-irradiated mouse embryonic fibroblast (MEF) cells - In MEF cells, IGF-1 signaling molecules were decreased and p21/phosphorylated p38 were increased by {gamma}-irradiation - The experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 signaling is involved but not essential in radiation-induced cell growth arrest and senescence and that p38 MAP kinase play a important role in this cellular radiation response. The role of IGF-1 and p38 signaling in {gamma}-irradiated mouse fibroblast (NIH/3T3) cell - In NIH/3T3 cells, IGF-1 signaling molecules and p21/phosphorylated p38 were increased by {gamma} -irradiation. - However, the experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 and p38 signaling do not play a crucial role in radiation-induced cell growth arrest and senescence in NIH/3T3 cells. Effects of {gamma}-irradiation on the expressions and activations on the genes related to the IGF-1 signaling in mouse tissues - In {gamma}-irradiated mice, the increased expressions of IGF-1 and IGF-1R were observed in the lung and kidney at 2 months after irradiation, and in all the tissues examined (lung, liver and kidney) at 6 months after irradiation. - In the lung of {gamma}-irradiated mice at 6 months after irradiation, the increases of IGF-1R, phosphorylated FOXO3a, p65, p38, p21 were observed. - The

Investigation on the role of IGF-1 signal transduction in the biological radiation responses

International Nuclear Information System (INIS)

Jung, U Hee; Jo, Sung Kee; Park, Hae Ran; Oh, Soo Jin; Cho, Eun Hee; Eom, Hyun Soo; Ju, Eun Jin

2009-05-01

Effects of γ-irradiation on the IGF-1 related gene expressions and activations in various cell lines - Various expression patterns of IGF-1 and IGF-1R following γ-irradiation were observed according to the cell lines - The increased expressions of IGF-1 and IGF-1R were observed in Balb/3T3 and NIH/3T3 cells - Among the IGF-1 downstream signaling molecules, the phosphorylated ERK5 were not changed by γ-irradiation in all three examined cell lines, whereas the phosphorylated p65 were increased by γ -irradiation in all cell lines. The role of IGF-1 and p38 signaling in γ-irradiated mouse embryonic fibroblast (MEF) cells - In MEF cells, IGF-1 signaling molecules were decreased and p21/phosphorylated p38 were increased by γ-irradiation - The experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 signaling is involved but not essential in radiation-induced cell growth arrest and senescence and that p38 MAP kinase play a important role in this cellular radiation response. The role of IGF-1 and p38 signaling in γ-irradiated mouse fibroblast (NIH/3T3) cell - In NIH/3T3 cells, IGF-1 signaling molecules and p21/phosphorylated p38 were increased by γ -irradiation. - However, the experiments with IGF-1R inhibitor (AG1024) and p38 inhibitor (SB203580) revealed that IGF-1 and p38 signaling do not play a crucial role in radiation-induced cell growth arrest and senescence in NIH/3T3 cells. Effects of γ-irradiation on the expressions and activations on the genes related to the IGF-1 signaling in mouse tissues - In γ-irradiated mice, the increased expressions of IGF-1 and IGF-1R were observed in the lung and kidney at 2 months after irradiation, and in all the tissues examined (lung, liver and kidney) at 6 months after irradiation. - In the lung of γ-irradiated mice at 6 months after irradiation, the increases of IGF-1R, phosphorylated FOXO3a, p65, p38, p21 were observed. - The patterns of altered expressions showed significant

Role of androgen receptor on cyclic mechanical stretch-regulated proliferation of C2C12 myoblasts and its upstream signals: IGF-1-mediated PI3K/Akt and MAPKs pathways.

Science.gov (United States)

Ma, Yiming; Fu, Shaoting; Lu, Lin; Wang, Xiaohui

2017-07-15

To detect the effects of androgen receptor (AR) on cyclic mechanical stretch-modulated proliferation of C2C12 myoblasts and its pathways: roles of IGF-1, PI3K and MAPK. C2C12 were randomly divided into five groups: un-stretched control, six or 8 h of fifteen percent stretch, and six or 8 h of twenty percent stretch. Cyclic mechanical stretch of C2C12 were completed using a computer-controlled FlexCell Strain Unit. Cell proliferation and IGF-1 concentration in medium were detected by CCK8 and ELISA, respectively. Expressions of AR and IGF-1R, and expressions and activities of PI3K, p38 and ERK1/2 in stretched C2C12 cells were determined by Western blot. ①The proliferation of C2C12 cells, IGF-1 concentration in medium, expressions of AR and IGF-1R, and activities of PI3K, p38 and ERK1/2 were increased by 6 h of fifteen percent stretch, while decreased by twenty percent stretch for six or 8 h ②The fifteen percent stretch-increased proliferation of C2C12 cells was reversed by AR inhibitor, Flutamide. ③The increases of AR expression, activities of PI3K, p38 and ERK1/2 resulted from fifteen percent stretch were attenuated by IGF-1 neutralizing antibody, while twenty percent stretch-induced decreases of the above indicators were enhanced by recombinant IGF-1. ④Specific inhibitors of p38, ERK1/2 and PI3K all decreased the expression of AR in fifteen percent and twenty percent of stretched C2C12 cells. Cyclic mechanical stretch modulated the proliferation of C2C12 cells, which may be attributed to the alterations of AR via IGF-1-PI3K/Akt and IGF-1-MAPK (p38, ERK1/2) pathways in C2C12 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

SiRNA-mediated IGF-1R inhibition sensitizes human colon cancer SW480 cells to radiation

International Nuclear Information System (INIS)

Yavari, Kamal; Taghikhani, Mohammad; Mesbah-Namin, Seyed A.; Maragheh, Mohammad Ghannadi; Babaei, Mohammad Hosein; Arfaee, Ali Jabbary; Madani, Hossein; Mirzaei, Hamid Reza

2010-01-01

Purpose. Insulin like growth factor receptor 1 (IGF-1R) is well-documented to play a key role in radiation response and tumor radiosensitivity, thus offering an attractive clinic drug target to enhance tumor sensitivity to anti-cancer radiotherapy. Material and methods. Human colon carcinoma SW480 cells were transfected with the specific small interference RNA (siRNA) expression vector (pkD-shRNA-IGF-1R-V2) designed to target IGF-1R mRNA. The expression of IGF-1R mRNA and its protein among the transfected and untransfected cells were detected by semi-quantitative RT-PCR and ELISA assay. The changes in cell radiosensitivity were examined by MTT assay. Results. Transfection of mammalian expression vector pkD containing IGF-1R siRNA was shown to reduce IGF-1R mRNA levels by up to 95%. ELISA assay detected a similar inhibition of IGF-1R protein levels in cells transfected with IGF-1R siRNA. SW480 cells transfected with the expression vector for siRNA significantly rendered cells more sensitive to radiation and the highest radiation enhancement ratio was 2.02 ± 0.08. Conclusion. These data provide the first evidence that specific siRNA fragment (pkD-shRNA-IGF-1R-V2) targeting human IGF-1R mRNA is able to enhance colon cancer radiosensitivity. Also results indicated that, combining IGF-1R siRNA and radiation significantly enhances antitumor efficacy compared with either modality alone

The relationship between maternal insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and IGFBP-3 to gestational age and preterm delivery.

LENUS (Irish Health Repository)

Cooley, Sharon M

2010-05-01

To investigate the relationship between levels of insulin-like growth factors 1 and 2 (IGF-1, IGF-2), and insulin-like growth factor binding protein 3 (IGFBP-3) in antenatal maternal serum and gestational age at delivery.

study on the serum levels of E2, IL-6 and IGF-I in patients with post-menopausal osteoporosis (PMO)

International Nuclear Information System (INIS)

Lv Kuan; Liu Chunyu; Lu Yingju

2006-01-01

Objective: To study the changes of serum levels of E 2 , IL-6, IGF-I in patients with post-menopausal osteoporosis (PMO). Methods: Serum levels of E 2 (with CLIA), IL-6, IGF-I, BGP (with RIA) were measured in the following subjects: (1) 32 patients with PMO (2) 32 post-menopausal women without PMO and (3) 30 pre-menopausal controls. Serum P, Ca and AKP levels were also determined. Results: As a whole, serum levels of IL -6 in postmenopausal women were higher than those in controls. Levels in subjects with PMO were significantly higher than those without PMO (P 2 and BMD index (r=-0. 587, - 0. 438 respectively, P 2 and BMD index (r=0.569, 0.433 respectively, P 2 levels will in someway promote the expression of IL-6 ( osteoclastic) and reduce the expression of IGF-I (osteoclastic), resulting in lessening of bone mass. HRT, despite of the controversy over cardio-vascalar safety, is beneficial for osteoporosis. (authors)

Expression and imprinting of DIO3 and DIO3OS genes in Holstein ...

Indian Academy of Sciences (India)

Navya

2016-10-18

Oct 18, 2016 ... expressed from the paternal allele, while the DIO3OS transcript is ..... interactions, or via transcriptional occlusion mechanisms (e.g. Kanduri ... The IG-DMR is associated with proper imprinting of linked genes on the maternal.

The strength of small: Improved targeting of Insulin-like Growth Factor-1 Receptor (IGF-1R) with F(ab')2-R1507 fragments in Ewing sarcomas

NARCIS (Netherlands)

Fleuren, Emmy D. G.; Versleijen-Jonkers, Yvonne M. H.; Heskamp, Sandra; Roeffen, Melissa H. S.; Bouwman, Wilbert H.; Molkenboer-Kuenen, Janneke D. M.; van Laarhoven, Hanneke W. M.; Oyen, Wim J. G.; Boerman, Otto C.; van der Graaf, Winette T. A.

2013-01-01

To investigate whether F(ab')2-fragments of the monoclonal Insulin-like Growth Factor-1 Receptor (IGF-1R) antibody R1507 (F(ab')2-R1507) can successfully target IGF-1R in Ewing sarcomas (ES). BALB/c nude mice were subcutaneously implanted with IGF-1R-expressing human ES xenografts (EW-5 and EW-8)

IGF-1R signaling in chondrocytes modulates growth plate development by interacting with the PTHrP/Ihh pathway.

Science.gov (United States)

Wang, Yongmei; Cheng, Zhiqiang; Elalieh, Hashem Z; Nakamura, Eiichiro; Nguyen, Minh-Thanh; Mackem, Susan; Clemens, Thomas L; Bikle, Daniel D; Chang, Wenhan

2011-07-01

Systemic derangements and perinatal death of generalized insulin-like growth factor 1 (IGF-1) and IGF-1 receptor (IGF-1R) knockout mice preclude definitive assessment of IGF-1R actions in growth-plate (GP) chondrocytes. We generated cartilage-specific Igf1r knockout ((Cart) Igf1r(-/-)) mice to investigate local control of chondrocyte differentiation in the GP by this receptor. These mice died shortly after birth and showed disorganized chondrocyte columns, delayed ossification and vascular invasion, decreased cell proliferation, increased apoptosis, and increased expression of parathyroid hormone-related protein (Pthrp) RNA and protein in their GPs. The increased Pthrp expression in the knockout GPs likely was due to an increase in gene transcription, as determined by the increased activity of a LacZ reporter that was inserted downstream of the endogenous PTHrP promoter and bred into the knockout mice. To circumvent the early death of (Cart) Igf1r(-/-) mice and investigate the role of IGF-1R during postnatal growth, we made tamoxifen (Tam)-inducible, cartilage-specific Igf1r knockout ((TamCart) Igf1r(-/-)) mice. At 2 weeks of age and 7 to 8 days after Tam injection, the (TamCart) Igf1r(-/-) mice showed growth retardation with a disorganized GP, reduced chondrocyte proliferation, decreased type 2 collagen and Indian Hedgehog (Ihh) expression, but increased expression of PTHrP. Consistent with in vivo observations, in vitro knockout of the Igf1r gene by adenoviral expression of Cre recombinase suppressed cell proliferation, promoted apoptosis, and increased Pthrp expression. Our data indicate that the IGF-1R in chondrocytes controls cell growth, survival, and differentiation in embryonic and postnatal GPs in part by suppression of Pthrp expression. Copyright © 2011 American Society for Bone and Mineral Research.

Aging, Atherosclerosis, and IGF-1

Science.gov (United States)

Higashi, Yusuke; Sukhanov, Sergiy; Anwar, Asif; Shai, Shaw-Yung

2012-01-01

Insulin-like growth factor 1 (IGF-1) is an endocrine and autocrine/paracrine growth factor that circulates at high levels in the plasma and is expressed in most cell types. IGF-1 has major effects on development, cell growth and differentiation, and tissue repair. Recent evidence indicates that IGF-1 reduces atherosclerosis burden and improves features of atherosclerotic plaque stability in animal models. Potential mechanisms for this atheroprotective effect include IGF-1–induced reduction in oxidative stress, cell apoptosis, proinflammatory signaling, and endothelial dysfunction. Aging is associated with increased vascular oxidative stress and vascular disease, suggesting that IGF-1 may exert salutary effects on vascular aging processes. In this review, we will provide a comprehensive update on IGF-1's ability to modulate vascular oxidative stress and to limit atherogenesis and the vascular complications of aging. PMID:22491965

GATM, the human ortholog of the mouse imprinted Gatm gene, escapes genomic imprinting in placenta

Directory of Open Access Journals (Sweden)

Toshinobu Miyamoto

2005-03-01

Full Text Available The GATM gene encodes L-arginine:glycine amidinotransferase, which catalyzes the conversion of L-arginine into guanidinoacetate, the rate-limiting step in the synthesis of creatine. Since, deficiencies in creatine synthesis and transport lead to certain forms of mental retardation in human, the human GATM gene appears to be involved in brain development. Recently it has been demonstrated that the mouse Gatm is expressed during development and is imprinted with maternal expression in the placenta and yolk sac, but not in embryonic tissues. We investigated the imprinting status of the human GATM by analyzing its expression in four human placentas. GATM was biallelically expressed, thus suggesting that this gene escapes genomic imprinting in placentas, differently from what has been reported in mouse extra-embryonic tissues.

Differential Role of Rapamycin in Epidermis-Induced IL-15-IGF-1 Secretion via Activation of Akt/mTORC2.

Science.gov (United States)

Bai, Yang; Xu, Rui; Zhang, Xueyuan; Zhang, Xiaorong; Hu, Xiaohong; Li, Yashu; Li, Haisheng; Liu, Meixi; Huang, Zhenggen; Yan, Rongshuai; He, Weifeng; Luo, Gaoxing; Wu, Jun

2017-01-01

Backgroud/Aims: The effects of rapamycin (RPM) on wound healing have been previously studied. However, reciprocal contradictory data have been reported, and the underlying mechanism remains unclear. This study aims to uncover differential role of RPM in regulation of wound healing and explore the possible mechanism. C57BL/6J mice and epidermal cells were treated with different doses of RPM. The wound re-epithelialization was observed by hematoxylin and eosin (HE) staining. The expression of IL-15 and IGF-1 were detected by immunohistochemistry and quantitative real-time PCR. Epidermal cell survival was determined by CCK-8 assays. Moreover, the mTORC1 and mTORC2 pathway were examined by western blot analysis. This study showed that differential doses of RPM could lead to separate consequences in epidermis. Histological analyses showed that low-dose RPM promoted wound healing, and enhanced the expression of IL-15 and IGF-1. Furthermore, western blot analysis showed that the effect of low-dose RPM in epidermis were not through mTORC1 pathway. Instead, activation of the Akt/mTORC2 pathway was involved in low-dose RPM-induced IL-15 and IGF-1 production in epidermis, while high-dose RPM inhibited the expression of IL-15 and IGF-1 and the activity of mTORC1 and mTORC2 pathway. This study for the first time demonstrated that RPM-mediated wound healing was dose-dependent. © 2017 The Author(s). Published by S. Karger AG, Basel.

IGF-1 prevents ANG II-induced skeletal muscle atrophy via Akt- and Foxo-dependent inhibition of the ubiquitin ligase atrogin-1 expression

Science.gov (United States)

Yoshida, Tadashi; Semprun-Prieto, Laura; Sukhanov, Sergiy

2010-01-01

Congestive heart failure is associated with activation of the renin-angiotensin system and skeletal muscle wasting. Angiotensin II (ANG II) has been shown to increase muscle proteolysis and decrease circulating and skeletal muscle IGF-1. We have shown previously that skeletal muscle-specific overexpression of IGF-1 prevents proteolysis and apoptosis induced by ANG II. These findings indicated that downregulation of IGF-1 signaling in skeletal muscle played an important role in the wasting effect of ANG II. However, the signaling pathways and mechanisms whereby IGF-1 prevents ANG II-induced skeletal muscle atrophy are unknown. Here we show ANG II-induced transcriptional regulation of two ubiquitin ligases atrogin-1 and muscle ring finger-1 (MuRF-1) that precedes the reduction of skeletal muscle IGF-1 expression, suggesting that activation of atrogin-1 and MuRF-1 is an initial mechanism leading to skeletal muscle atrophy in response to ANG II. IGF-1 overexpression in skeletal muscle prevented ANG II-induced skeletal muscle wasting and the expression of atrogin-1, but not MuRF-1. Dominant-negative Akt and constitutively active Foxo-1 blocked the ability of IGF-1 to prevent ANG II-mediated upregulation of atrogin-1 and skeletal muscle wasting. Our findings demonstrate that the ability of IGF-1 to prevent ANG II-induced skeletal muscle wasting is mediated via an Akt- and Foxo-1-dependent signaling pathway that results in inhibition of atrogin-1 but not MuRF-1 expression. These data suggest strongly that atrogin-1 plays a critical role in mechanisms of ANG II-induced wasting in vivo. PMID:20228261

The impact of the IGF-1 system of cancer cells on radiation response - An in vitro study.

Science.gov (United States)

Venkatachalam, Senthiladipan; Mettler, Esther; Fottner, Christian; Miederer, Matthias; Kaina, Bernd; Weber, Matthias M

2017-12-01

Overexpression of the insulin-like growth factor-1 receptor (IGF-1R) is associated with increased cell proliferation, differentiation, transformation, and tumorigenicity. Additionally, signaling involved in the resistance of cancer cells to radiotherapy originates from IGF-1R. The purpose of this study was to investigate the role of the IGF-1 system in the radiation response and further evaluate its effect on the expression of DNA repair pathway genes. To inhibit the IGF-1 system, we stably transfected the Caco-2 cell line to express a kinase-deficient IGF-1R mutant. We then studied the effects of this mutation on cell growth, the response to radiation, and clonogenic survival, as well as using a cell viability assay to examine DNA damage and repair. Finally, we performed immunofluorescence for γ-H2AX to examine double-strand DNA breaks and evaluated the expression of 84 key genes involved in DNA repair with a real-time PCR array. Mutant IGF-1R cells exhibited significantly blunted cell growth and viability, compared to wild-type cells, as well as reduced clonogenic survival after γ-irradiation. However, mutant IGF-1R cells did not show any significant delays in the repair of radiation-induced DNA double-strand breaks. Furthermore, expression of mutant IGF-1R significantly down-regulated the mRNA levels of BRCA2, a major protein involved in homologous recombination DNA repair. These results indicate that blocking the IGF-1R-mediated signaling cascade, through the expression of a kinase-deficient IGF-1R mutant, reduces cell growth and sensitizes cancer cells to ionizing radiation. Therefore, the IGF-1R system could be a potential target to enhance radio-sensitivity and the efficacy of cancer treatments.

Non-additive effects of RBP4, ESR1 and IGF2 polymorphisms on litter size at different parities in a Chinese-European porcine line

Directory of Open Access Journals (Sweden)

Alves Estefânia

2010-06-01

Full Text Available Abstract Background The aim of this work was to study the effects on litter size of variants of the porcine genes RBP4, ESR1 and IGF2, currently used in genetic tests for different purposes. Moreover, we investigated a possible effect of the interaction between RBP4-MspI and ESR1-PvuII polymorphisms. The IGF2-intron3-G3072A polymorphism is actually used to select lean growth, but other possible effects of this polymorphism on reproductive traits need to be evaluated. Methods Detection of polymorphisms in the genomic and cDNA sequences of RBP4 gene was carried out. RBP4-MspI and IGF2-intron3-G3072A were genotyped in a hyperprolific Chinese-European line (Tai-Zumu and three new RBP4 polymorphisms were genotyped in different pig breeds. A bivariate animal model was implemented in association analyses considering the number of piglets born alive at early (NBA12 and later parities (NBA3+ as different traits. A joint analysis of RBP4-MspI and ESR1-PvuII was performed to test their possible interaction. In the IGF2 analysis, paternal or maternal imprinting effects were also considered. Results Four different RBP4 haplotypes were detected (TGAC, GGAG, GAAG and GATG in different pig breeds and wild boars. A significant interaction effect between RBP4-MspI and ESR1-PvuII polymorphisms of 0.61 ± 0.29 piglets was detected on NBA3+. The IGF2 analysis revealed a significant increase on NBA3+ of 0.74 ± 0.37 piglets for the paternally inherited allele A. Conclusions All the analyzed pig and wild boar populations shared one of the four detected RBP4 haplotypes. This suggests an ancestral origin of the quoted haplotype. The joint use of RBP4-MspI and ESR1-PvuII polymorphisms could be implemented to select for higher prolificacy in the Tai-Zumu line. In this population, the paternal allele IGF2-intron3-3072A increased litter size from the third parity. The non-additive effects on litter size reported here should be tested before implementation in other pig

The level of insulin growth factor-1 receptor expression is directly correlated with the tumor uptake of {sup 111}In-IGF-1(E3R) in vivo and the clonogenic survival of breast cancer cells exposed in vitro to trastuzumab (Herceptin)

Energy Technology Data Exchange (ETDEWEB)

Cornelissen, Bart; McLarty, Kristin; Kersemans, Veerle [Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Reilly, Raymond M. [Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Department of Medical Imaging, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Toronto General Research Institute, University Health Network Toronto, Toronto, ON, M5S 3M2 (Canada)], E-mail: raymond.reilly@utoronto.ca

2008-08-15

Introduction: Our objective was to define the relationships between tumor uptake of [{sup 111}In]-IGF-1 and [{sup 111}In]-IGF-1(E3R), an analogue which does not bind insulin growth factor-1 (IGF-1) binding proteins (i.e., IGFBP-3), and the level of IGF-1 receptor (IGF-1R) expression on human breast cancer (BC) xenografts in athymic mice, as well as the feasibility for tumor imaging. A second objective was to correlate IGF-1R (and HER2 density) with the cytotoxicity of trastuzumab in the absence/presence of IGFBP-3 or the IGF-1R tyrosine kinase inhibitor, AG1024. Methods: The tumor and normal tissue uptake of [{sup 111}In]-IGF-1 and [{sup 111}In]-IGF-1(E3R) were determined at 4 h postinjection in mice implanted subcutaneously with MDA-MB-231, H2N, HR2 or MCF-7/HER2-18 human BC xenografts (8.5x10{sup 4}, 1.4x10{sup 4}, 4.0x10{sup 4} and 1.0x10{sup 5} IGF-1R/cell, respectively). The effect of co-injection of IGF-1 (50 {mu}g) or IGFBP-3 (2 or 25 {mu}g) was studied. The relationship between tumor uptake of [{sup 111}In]-IGF-1(E3R) and IGF-1R density was examined. MicroSPECT/CT imaging was performed on mice with MCF-7/HER2-18 tumors injected with [{sup 111}In]-IGF-1(E3R). The surviving fraction of BC cells exposed to trastuzumab (67.5 {mu}g/ml) in the absence/presence of IGFBP-3 (1 {mu}g/ml) or the IGF-1R kinase inhibitor, AG1024 (1 or 5 {mu}g/ml), was determined. Results: [{sup 111}In]-IGF-1 was specifically taken up by MCF-7/HER2-18 xenografts; tumor uptake was decreased twofold when co-injected with IGF-1 (1.9{+-}0.1 vs. 1.0{+-}0.1 %ID/g). Co-injection of IGBP-3 decreased kidney uptake of [{sup 111}In]-IGF-1 up to twofold and increased circulating radioactivity threefold. There was a strong linear correlation (r{sup 2}=0.99) between the tumor uptake of {sup 111}In-IGF-1(E3R) and IGF-1R density. Tumor uptake ranged from 0.4{+-}0.05 %ID/g for H2N to 2.5{+-}0.5 %ID/g for MCF-7/HER2-18 xenografts. MCF-7/HER2-18 tumors were visualized by microSPECT/CT. Resistance of BC

The level of insulin growth factor-1 receptor expression is directly correlated with the tumor uptake of 111In-IGF-1(E3R) in vivo and the clonogenic survival of breast cancer cells exposed in vitro to trastuzumab (Herceptin)

International Nuclear Information System (INIS)

Cornelissen, Bart; McLarty, Kristin; Kersemans, Veerle; Reilly, Raymond M.

2008-01-01

Introduction: Our objective was to define the relationships between tumor uptake of [ 111 In]-IGF-1 and [ 111 In]-IGF-1(E3R), an analogue which does not bind insulin growth factor-1 (IGF-1) binding proteins (i.e., IGFBP-3), and the level of IGF-1 receptor (IGF-1R) expression on human breast cancer (BC) xenografts in athymic mice, as well as the feasibility for tumor imaging. A second objective was to correlate IGF-1R (and HER2 density) with the cytotoxicity of trastuzumab in the absence/presence of IGFBP-3 or the IGF-1R tyrosine kinase inhibitor, AG1024. Methods: The tumor and normal tissue uptake of [ 111 In]-IGF-1 and [ 111 In]-IGF-1(E3R) were determined at 4 h postinjection in mice implanted subcutaneously with MDA-MB-231, H2N, HR2 or MCF-7/HER2-18 human BC xenografts (8.5x10 4 , 1.4x10 4 , 4.0x10 4 and 1.0x10 5 IGF-1R/cell, respectively). The effect of co-injection of IGF-1 (50 μg) or IGFBP-3 (2 or 25 μg) was studied. The relationship between tumor uptake of [ 111 In]-IGF-1(E3R) and IGF-1R density was examined. MicroSPECT/CT imaging was performed on mice with MCF-7/HER2-18 tumors injected with [ 111 In]-IGF-1(E3R). The surviving fraction of BC cells exposed to trastuzumab (67.5 μg/ml) in the absence/presence of IGFBP-3 (1 μg/ml) or the IGF-1R kinase inhibitor, AG1024 (1 or 5 μg/ml), was determined. Results: [ 111 In]-IGF-1 was specifically taken up by MCF-7/HER2-18 xenografts; tumor uptake was decreased twofold when co-injected with IGF-1 (1.9±0.1 vs. 1.0±0.1 %ID/g). Co-injection of IGBP-3 decreased kidney uptake of [ 111 In]-IGF-1 up to twofold and increased circulating radioactivity threefold. There was a strong linear correlation (r 2 =0.99) between the tumor uptake of 111 In-IGF-1(E3R) and IGF-1R density. Tumor uptake ranged from 0.4±0.05 %ID/g for H2N to 2.5±0.5 %ID/g for MCF-7/HER2-18 xenografts. MCF-7/HER2-18 tumors were visualized by microSPECT/CT. Resistance of BC cells to trastuzumab was directly associated with IGF-1R expression, despite co-expression

Experimental approach to IGF-1 therapy in CCl4-induced acute liver damage in healthy controls and mice with partial IGF-1 deficiency.

Science.gov (United States)

Morales-Garza, Luis A; Puche, Juan E; Aguirre, Gabriel A; Muñoz, Úrsula; García-Magariño, Mariano; De la Garza, Rocío G; Castilla-Cortazar, Inma

2017-05-04

Cell necrosis, oxidative damage, and fibrogenesis are involved in cirrhosis development, a condition in which insulin-like growth factor 1 (IGF-1) levels are diminished. This study evaluates whether the exogenous administration of low doses of IGF-1 can induce hepatoprotection in acute carbon tetrachloride (CCl 4 )-induced liver damage compared to healthy controls (Wt Igf +/+ ). Additionally, the impact of IGF-1 deficiency on a damaged liver was investigated in mice with a partial deficit of this hormone (Hz Igf1 +/- ). Three groups of 25 ± 5-week-old healthy male mice (Wt Igf +/+ ) were included in the protocol: untreated controls (Wt). Controls that received CCl 4 (Wt + CCl 4 ) and Wt + CCl 4 were treated subcutaneously with IGF-1 (2 µg/100 g body weight/day) for 10 days (Wt + CCl 4  + IGF1). In parallel, three IGF-1-deficient mice (Hz Igf1 +/- ) groups were studied: untreated Hz, Hz + CCl 4 , and Hz + CCl 4  + IGF-1. Microarray and real-time quantitative polymerase chain reaction (RT-qPCR) analyses, serum aminotransferases levels, liver histology, and malondialdehyde (MDA) levels were assessed at the end of the treatment in all groups. All data represent mean ± SEM. An altered gene coding expression pattern for proteins of the extracellular matrix, fibrosis, and cellular protection were found, as compared to healthy controls, in which IGF-1 therapy normalized in the series including healthy mice. Liver histology showed that Wt + CCl 4  + IGF1 mice had less oxidative damage, fibrosis, lymphocytic infiltrate, and cellular changes when compared to the Wt + CCl 4 . Moreover, there was a correlation between MDA levels and the histological damage score (Pearson's r = 0.858). In the IGF-1-deficient mice series, similar findings were identified, denoting a much more vulnerable hepatic parenchyma. IGF1 treatment improved the biochemistry, histology, and genetic expression of pro-regenerative and cytoprotective factors in both series

Circulating IGF1 regulates hippocampal IGF1 levels and brain gene expression during adolescence

OpenAIRE

Yan, Han; Mitschelen, Matthew; Bixler, Georgina V; Brucklacher, Robert M; Farley, Julie A; Han, Song; Freeman, Willard M; Sonntag, William E

2011-01-01

GH and its anabolic mediator, IGF1, are important not only in somatic growth but also in the regulation of brain function. Even though GH treatment has been used clinically to improve body composition and exercise capacity in adults, its influence on central nervous system function has only recently been recognized. This is also the case for children with childhood-onset GH deficiency (GHD) where GH has been used to stimulate bone growth and enhance final adult height. Circulating IGF1 is tra...

Comparative anatomy of chromosomal domains with imprinted and non-imprinted allele-specific DNA methylation.

Science.gov (United States)

Paliwal, Anupam; Temkin, Alexis M; Kerkel, Kristi; Yale, Alexander; Yotova, Iveta; Drost, Natalia; Lax, Simon; Nhan-Chang, Chia-Ling; Powell, Charles; Borczuk, Alain; Aviv, Abraham; Wapner, Ronald; Chen, Xiaowei; Nagy, Peter L; Schork, Nicholas; Do, Catherine; Torkamani, Ali; Tycko, Benjamin

2013-08-01

Allele-specific DNA methylation (ASM) is well studied in imprinted domains, but this type of epigenetic asymmetry is actually found more commonly at non-imprinted loci, where the ASM is dictated not by parent-of-origin but instead by the local haplotype. We identified loci with strong ASM in human tissues from methylation-sensitive SNP array data. Two index regions (bisulfite PCR amplicons), one between the C3orf27 and RPN1 genes in chromosome band 3q21 and the other near the VTRNA2-1 vault RNA in band 5q31, proved to be new examples of imprinted DMRs (maternal alleles methylated) while a third, between STEAP3 and C2orf76 in chromosome band 2q14, showed non-imprinted haplotype-dependent ASM. Using long-read bisulfite sequencing (bis-seq) in 8 human tissues we found that in all 3 domains the ASM is restricted to single differentially methylated regions (DMRs), each less than 2kb. The ASM in the C3orf27-RPN1 intergenic region was placenta-specific and associated with allele-specific expression of a long non-coding RNA. Strikingly, the discrete DMRs in all 3 regions overlap with binding sites for the insulator protein CTCF, which we found selectively bound to the unmethylated allele of the STEAP3-C2orf76 DMR. Methylation mapping in two additional genes with non-imprinted haplotype-dependent ASM, ELK3 and CYP2A7, showed that the CYP2A7 DMR also overlaps a CTCF site. Thus, two features of imprinted domains, highly localized DMRs and allele-specific insulator occupancy by CTCF, can also be found in chromosomal domains with non-imprinted ASM. Arguing for biological importance, our analysis of published whole genome bis-seq data from hES cells revealed multiple genome-wide association study (GWAS) peaks near CTCF binding sites with ASM.

Comparative anatomy of chromosomal domains with imprinted and non-imprinted allele-specific DNA methylation.

Directory of Open Access Journals (Sweden)

Anupam Paliwal

2013-08-01

Full Text Available Allele-specific DNA methylation (ASM is well studied in imprinted domains, but this type of epigenetic asymmetry is actually found more commonly at non-imprinted loci, where the ASM is dictated not by parent-of-origin but instead by the local haplotype. We identified loci with strong ASM in human tissues from methylation-sensitive SNP array data. Two index regions (bisulfite PCR amplicons, one between the C3orf27 and RPN1 genes in chromosome band 3q21 and the other near the VTRNA2-1 vault RNA in band 5q31, proved to be new examples of imprinted DMRs (maternal alleles methylated while a third, between STEAP3 and C2orf76 in chromosome band 2q14, showed non-imprinted haplotype-dependent ASM. Using long-read bisulfite sequencing (bis-seq in 8 human tissues we found that in all 3 domains the ASM is restricted to single differentially methylated regions (DMRs, each less than 2kb. The ASM in the C3orf27-RPN1 intergenic region was placenta-specific and associated with allele-specific expression of a long non-coding RNA. Strikingly, the discrete DMRs in all 3 regions overlap with binding sites for the insulator protein CTCF, which we found selectively bound to the unmethylated allele of the STEAP3-C2orf76 DMR. Methylation mapping in two additional genes with non-imprinted haplotype-dependent ASM, ELK3 and CYP2A7, showed that the CYP2A7 DMR also overlaps a CTCF site. Thus, two features of imprinted domains, highly localized DMRs and allele-specific insulator occupancy by CTCF, can also be found in chromosomal domains with non-imprinted ASM. Arguing for biological importance, our analysis of published whole genome bis-seq data from hES cells revealed multiple genome-wide association study (GWAS peaks near CTCF binding sites with ASM.

The epigenetic control of transposable elements and imprinted genes in newborns is affected by the mode of conception: ART versus spontaneous conception without underlying infertility.

Science.gov (United States)

Choux, C; Binquet, C; Carmignac, V; Bruno, C; Chapusot, C; Barberet, J; Lamotte, M; Sagot, P; Bourc'his, D; Fauque, P

2018-02-01

Do assisted reproductive technologies alter DNA methylation and/or transcription of transposable elements and imprinted genes in cord blood and placenta? After ART, DNA methylation and/or transcription changes of some transposable elements and imprinted genes were found in placenta samples while transcription modifications for some transposable elements were also discovered in cord blood. Recent studies have confirmed the increased risk of placenta-related adverse pregnancy outcomes and the excess of imprinted disorders with abnormal methylation patterns after ART, which raises the issue of a potential ART-induced epigenetic risk. A total of 51 IVF/ICSI (15 conventional and 36 ICSI) singleton pregnancies were prospectively included from January 2013 to April 2015 and compared to 48 spontaneously conceived singleton pregnancies. The DNA methylation and transcription of three imprinted loci (H19/IGF2, KCNQ1OT1 and SNURF DMRs) and four transposon families (LINE-1, ERVFRD, AluYa5 and ERVW) in cord blood and placenta obtained at birth were assessed by pyrosequencing and quantitative RT-PCR, respectively. All data were adjusted for gestational age at delivery, sex of the newborn, parity and maternal age. DNA methylation levels of H19/IGF2, KCNQ1OT1, LINE-1Hs and ERVFRD-1 were significantly lower in IVF/ICSI placentas than in control placentas, while there was no difference for cord blood. Moreover, the expression of ERVFRD-1 and LINE-1 ORF2 in cord blood and ERVFRD-1 in placenta was lower in the IVF/ICSI group than in controls. The expression of ERVFRD-1 in placenta correlated positively with birth weight and placenta weight, but only in the control group, thus pointing to the potential deregulation of syncytin function after ART. N/A. The control group of fertile couples having conceived within 1 year prevented us from deciphering the distinct roles of ART and infertility. These novel findings of ERVFRD (syncytin-2) expression correlating with birth weight and placenta

A novel large deletion of the ICR1 region including H19 and putative enhancer elements.

Science.gov (United States)

Fryssira, Helen; Amenta, Stella; Kanber, Deniz; Sofocleous, Christalena; Lykopoulou, Evangelia; Kanaka-Gantenbein, Christina; Cerrato, Flavia; Lüdecke, Hermann-Josef; Bens, Susanne; Riccio, Andrea; Buiting, Karin

2015-05-06

Beckwith-Wiedemann syndrome (BWS) is a rare pediatric overgrowth disorder with a variable clinical phenotype caused by deregulation affecting imprinted genes in the chromosomal region 11p15. Alterations of the imprinting control region 1 (ICR1) at the IGF2/H19 locus resulting in biallelic expression of IGF2 and biallelic silencing of H19 account for approximately 10% of patients with BWS. The majority of these patients have epimutations of the ICR1 without detectable DNA sequence changes. Only a few patients were found to have deletions. Most of these deletions are small affecting different parts of the ICR1 differentially methylated region (ICR1-DMR) removing target sequences for CTCF. Only a very few deletions reported so far include the H19 gene in addition to the CTCF binding sites. None of these deletions include IGF2. A male patient was born with hypotonia, facial dysmorphisms and hypoglycemia suggestive of Beckwith-Wiedemann syndrome. Using methylation-specific (MS)-MLPA (Multiplex ligation-dependent probe amplification) we have identified a maternally inherited large deletion of the ICR1 region in a patient and his mother. The deletion results in a variable clinical expression with a classical BWS in the mother and a more severe presentation of BWS in her son. By genome-wide SNP array analysis the deletion was found to span ~100 kb genomic DNA including the ICR1DMR, H19, two adjacent non-imprinted genes and two of three predicted enhancer elements downstream to H19. Methylation analysis by deep bisulfite next generation sequencing revealed hypermethylation of the maternal allele at the IGF2 locus in both, mother and child, although IGF2 is not affected by the deletion. We here report on a novel large familial deletion of the ICR1 region in a BWS family. Due to the deletion of the ICR1-DMR CTCF binding cannot take place and the residual enhancer elements have access to the IGF2 promoters. The aberrant methylation (hypermethylation) of the maternal IGF2

miR-598 acts as a tumor suppressor in human gastric cancer by targeting IGF-1R.

Science.gov (United States)

Liu, Na; Yang, Hua; Wang, Hong

2018-01-01

In recent years, the aberrant expression of miR-598 in tumorigenesis has been demonstrated, as well as the fact that the IGF-1R pathway is also involved in the development of human gastric cancer (GC). The present study aimed to investigate the molecular mechanisms underlying miR-598-regulated IGF-1R expression in human GC. We analyzed the expression of miR-598 and IGF-1R in GC samples and cells, and evaluated the clinical significance of miR-598 and IGF-1R in GC patients. Furthermore, in vitro and in vivo assays were used to investigate the molecular mechanisms of miR-598 and IGF-1R. miR-598 expression was frequently downregulated in GC tissues and cells, and significantly correlated with poor prognosis, vascular invasion, TNM stage, and lymph node metastases as well as IGF-1R expression. The overexpression of miR-598 obviously inhibited cell proliferation, migration, invasion, and induced cell cycle arrest in the G1/S phase, and increased the apoptosis of GC cells. The overexpression of miR-598 also significantly inhibited ERK1/2 and Akt phosphorylation level. In vivo assay validated the inhibitory effect of miR-598 on tumor growth. Further studies showed that miR-598 inhibited IGF-1R protein expression by directly targeting its 3'-UTR. Besides, over-expression of IGF-1R reversed the inhibitory effects of miR-598, while suppression of IGF-1R expression showed inverse effects. miR-598 suppresses GC cell proliferation, migration and invasion by directly targeting IGF-1R expression. Thus, miR-598 may be a useful target for GC patients.

Imp2 regulates GBM progression by activating IGF2/PI3K/Akt pathway.

Science.gov (United States)

Mu, Qingchun; Wang, Lijun; Yu, Fengbo; Gao, Haijun; Lei, Ting; Li, Peiwen; Liu, Pengfei; Zheng, Xu; Hu, Xitong; Chen, Yong; Jiang, Zhenfeng; Sayari, Arash J; Shen, Jia; Huang, Haiyan

2015-01-01

Glioblastomas multiforme (GBM) are the most frequently occurring malignant brain cancers. Treatment for GBM consists of surgical resection and subsequent adjuvant radiation therapy and chemotherapy. Despite this, GBM patient survival is limited to 12-15 months, and researchers are continually trying to develop improved therapy options. Insulin-like growth factor 2 mRNA-binding protein 2 (Imp2) is known to be upregulated in many cancers and is known to regulate the signaling activity of insulin-like growth factor 2 (IGF2). However, relatively little is known about its role in malignant development of GBM. In this study, we first found Imp2 is upregulated in GBM tissues by using clinical samples and public database search. Studies with loss and gain of Imp2 expression in in vitro GBM cell culture system demonstrated the role of Imp2 in promoting GBM cell proliferation, migration, invasion and epithelial-to-mesenchymal transition (EMT). Additionally, our results show that Imp2 regulates the activity of IGF2, which further activates PI3K/Akt signaling, thereby to promote GBM malignancy. Inhibition of Imp2 was also found to sensitize GBM to temozolomide treatment. These observations add to the current knowledge of GBM biology, and may prove useful in development of more effective GBM therapy.

Cell surface GRP78 facilitates hepatoma cells proliferation and migration by activating IGF-IR.

Science.gov (United States)

Yin, Yancun; Chen, Chen; Chen, Jinliang; Zhan, Renhui; Zhang, Qiang; Xu, Xiaoyan; Li, Defang; Li, Minjing

2017-07-01

The 78kDa glucose regulated protein (GRP78) is a multifunctional chaperone that is involved in a variety of cellular processes. Insulin like growth factor I receptor (IGF-IR) often aberrant expresses in many types of tumor cells. The IGF-IR signaling plays key roles in carcinogenesis and maintenance of the malignant phenotype. The crosstalk between GRP78 and IGF-IR molecules has not well been illuminated. Here, we demonstrated a reciprocal regulation of GRP78 expression and IGF-IR pathway activation. IGF-I induced GRP78 expression in hepatoma cells. IGF-IR knockdown or IGF-IR inhibitor repressed GRP78 expression. Both phosphatidylinositol 3-kianase (PI3K) and mitogen-activated protein kinase (MAPK) pathways involved in IGF-I induction of GRP78 expression. Interestingly, treatment of hepatoma cells with IGF-I re-distributes GRP78 from endoplasmic reticulum (ER) to cell surface and promotes its physical interaction with IGF-IR. Also, GRP78 promotes IGF-IR phosphorylation and activation. Blocked of GRP78 by small interfering RNA or inhibition of GRP78 function by (-)-epigallocatechin gallate (EGCG) blocks IGF-I induced IGF-IR phosphorylation and its downstream signaling. Further, blocked cell surface GRP78 with antibody inhibits IGF-I stimulated cellular proliferation and migration. These data reveal an essential role for the molecular chaperone GRP78 in IGF-IR signaling and implicate the use of GRP78 inhibitors in blocking IGF-IR signaling in hepatoma cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types.

Science.gov (United States)

Heinemeier, K M; Olesen, J L; Schjerling, P; Haddad, F; Langberg, H; Baldwin, K M; Kjaer, M

2007-02-01

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P effect of eccentric training was greater than concentric and isometric training (P tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training (P tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF (P effect than concentric (P tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.

Optimization of IGF-1R SPECT/CT Imaging Using In-111-Labeled F(ab ')(2) and Fab Fragments of Article the Monoclonal Antibody R1507

NARCIS (Netherlands)

Heskamp, Sandra; van Laarhoven, Hanneke W. M.; Molkenboer-Kuenen, Janneke D. M.; Bouwman, Wilbert H.; van der Graaf, Winette T. A.; Oyen, Wim J. G.; Boerman, Otto C.

2012-01-01

The insulin-like growth factor 1 receptor (IGF-1R) is a potential new target for the treatment of breast cancer. Patients with breast cancer lesions that express IGF-1R may benefit from treatment with anti-IGF-IR antibodies. IGF-1R expression can be visualized using radiolabeled R1507, a monoclonal

Altered gene expression in human placentas after IVF/ICSI.

Science.gov (United States)

Nelissen, Ewka C M; Dumoulin, John C M; Busato, Florence; Ponger, Loïc; Eijssen, Lars M; Evers, Johannes L H; Tost, Jörg; van Montfoort, Aafke P A

2014-12-01

Is gene expression in placental tissue of IVF/ICSI patients altered when compared with a spontaneously conceived group, and are these alterations due to loss of imprinting (LOI) in the case of imprinted genes? An altered imprinted gene expression of H19 and Pleckstrin homology-like domain family A member 2 (PHLDA2), which was not due to LOI, was observed in human placentas after IVF/ICSI and several biological pathways were significantly overrepresented and mostly up-regulated. Genomic imprinting plays an important role in placental biology and in placental adaptive responses triggered by external stimuli. Changes in placental development and function can have dramatic effects on the fetus and its ability to cope with the intrauterine environment. An increased frequency of placenta-related problems as well as an adverse perinatal outcome is seen in IVF/ICSI derived pregnancies, but the role of placental epigenetic deregulation is not clear yet. In this prospective cohort study, a total of 115 IVF/ICSI and 138 control couples were included during pregnancy. After applying several exclusion criteria (i.e. preterm birth or stillbirth, no placental samples, pregnancy complications or birth defects), respectively, 81 and 105 placentas from IVF/ICSI and control pregnancies remained for analysis. Saliva samples were collected from both parents. We quantitatively analysed the mRNA expression of several growth-related imprinted genes [H19, insulin-like growth factor 2 (IGF2), PHLDA2, cyclin-dependent kinase inhibitor 1C (CDKN1C), mesoderm-specific transcript homolog (MEST) isoform α and β by quantitative PCR] after standardization against three housekeeping genes [Succinate dehydrogenase A (SDHA), YWHAZ and TATA-binding protein (TBP)]. A quantitative allele-specific expression analysis of the differentially expressed imprinted genes was performed to investigate LOI, independent of the mechanism of imprinting. Furthermore, a microarray analysis was carried out (n = 10 in

IGF-IR promotes prostate cancer growth by stabilizing α5β1 integrin protein levels.

Directory of Open Access Journals (Sweden)

Aejaz Sayeed

Full Text Available Dynamic crosstalk between growth factor receptors, cell adhesion molecules and extracellular matrix is essential for cancer cell migration and invasion. Integrins are transmembrane receptors that bind extracellular matrix proteins and enable cell adhesion and cytoskeletal organization. They also mediate signal transduction to regulate cell proliferation and survival. The type 1 insulin-like growth factor receptor (IGF-IR mediates tumor cell growth, adhesion and inhibition of apoptosis in several types of cancer. We have previously demonstrated that β1 integrins regulate anchorage-independent growth of prostate cancer (PrCa cells by regulating IGF-IR expression and androgen receptor-mediated transcriptional functions. Furthermore, we have recently reported that IGF-IR regulates the expression of β1 integrins in PrCa cells. We have dissected the mechanism through which IGF-IR regulates β1 integrin expression in PrCa. Here we report that IGF-IR is crucial for PrCa cell growth and that β1 integrins contribute to the regulation of proliferation by IGF-IR. We demonstrate that β1 integrin regulation by IGF-IR does not occur at the mRNA level. Exogenous expression of a CD4 - β1 integrin cytoplasmic domain chimera does not interfere with such regulation and fails to stabilize β1 integrin expression in the absence of IGF-IR. This appears to be due to the lack of interaction between the β1 cytoplasmic domain and IGF-IR. We demonstrate that IGF-IR stabilizes the β1 subunit by protecting it from proteasomal degradation. The α5 subunit, one of the binding partners of β1, is also downregulated along with β1 upon IGF-IR knockdown while no change is observed in the expression of the α2, α3, α4, α6 and α7 subunits. Our results reveal a crucial mechanistic role for the α5β1 integrin, downstream of IGF-IR, in regulating cancer growth.

The evolution of imprinting: chromosomal mapping of orthologues of mammalian imprinted domains in monotreme and marsupial mammals

Directory of Open Access Journals (Sweden)

Dunham Ian

2007-09-01

Full Text Available Abstract Background The evolution of genomic imprinting, the parental-origin specific expression of genes, is the subject of much debate. There are several theories to account for how the mechanism evolved including the hypothesis that it was driven by the evolution of X-inactivation, or that it arose from an ancestrally imprinted chromosome. Results Here we demonstrate that mammalian orthologues of imprinted genes are dispersed amongst autosomes in both monotreme and marsupial karyotypes. Conclusion These data, along with the similar distribution seen in birds, suggest that imprinted genes were not located on an ancestrally imprinted chromosome or associated with a sex chromosome. Our results suggest imprinting evolution was a stepwise, adaptive process, with each gene/cluster independently becoming imprinted as the need arose.

No preclinical rationale for IGF1R directed therapy in chondrosarcoma of bone.

Science.gov (United States)

Peterse, Elisabeth F P; Cleven, Arjen H G; De Jong, Yvonne; Briaire-de Bruijn, Inge; Fletcher, Jonathan A; Danen, Erik H J; Cleton-Jansen, Anne-Marie; Bovée, Judith V M G

2016-07-14

Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of the role of the IGF pathway in chondrosarcoma to determine if it can be a target for therapy, which was therefore explored in this study. Expression of mediators of IGF1R signalling and phosphorylation status of IRS1 was determined in chondrosarcoma cell lines by qRT-PCR and western blot. The effect of activation and inhibition of IGF1R signalling on downstream targets was assessed by western blot. Ten chondrosarcoma cell lines were treated with OSI-906 (IGF1R and IR dual inhibitor) after which cell proliferation and migration were determined by a viability assay and the xCELLigence system, respectively. In addition, four chondrosarcoma cell lines were treated with a combination of doxorubicin and OSI-906. By immunohistochemistry, IGF1R expression levels were determined in tissue microarrays of 187 cartilage tumours and ten paraffin embedded cell lines. Mediators of IGF1R signalling are heterogeneously expressed and phosphorylated IRS1 was detected in 67 % of the tested chondrosarcoma cell lines, suggesting that IGF1R signalling is active in a subset of chondrosarcoma cell lines. In the cell lines with phosphorylated IRS1, inhibition of IGF1R signalling decreased phosphorylated Akt levels and increased IGF1R expression, but it did not influence MAPK or S6 activity. In line with these findings, treatment with IGF1R/IR inhibitors did not impact proliferation or migration in any of the chondrosarcoma cell lines, even upon stimulation with IGF1. Although synergistic effects of IGF1R/IR inhibition with doxorubicin are described for other cancers, our results demonstrate that this was not the case for chondrosarcoma. In addition, we found minimal IGF1R expression in primary tumours in contrast to the high expression detected in chondrosarcoma cell lines, even if both were derived from the

Preeclampsia is associated with hypermethylation of IGF-1 promoter mediated by DNMT1.

Science.gov (United States)

Ma, Min; Zhou, Qiong-Jie; Xiong, Yu; Li, Bin; Li, Xiao-Tian

2018-01-01

Previous studies have demonstrated a dynamic epigenetic regulation of genes expression in placenta trophoblasts and a dynamic imbalance of DNA methylation and hydroxymethylation. Reduced IGF-1 has been observed in preeclampsia. This study was to investigate the interactive roles between IGF-1 and the global DNA methylation/hydroxymethylation, and the status of DNA methylation/hydroxymethylation and associated enzymes such as DNMTs and TETs in peeeclamptic placentas and hypoxic trophoblasts. It was found that IGF-1 was decreased in preeclamptic placentas and hypoxic trophoblasts when compared to the control group using immunohistochemisty, western blot, qRT-PCR and ELISA. Pyrophosphate sequencing showed IGF-1 promoter was significantly hypermethylated in preeclamptic placentas, which was responsible for reduced IGF-1 expression. Preeclamptic placentas and hypoxic trophoblasts were hypermethylated and hypohydroxymethylated accompanied by remarkably higher 5mC, DNMT1 and DNMT3b, and lower DNMT3a, 5hmC, TET1, TET2 and TET3 detected by immunohistochemisty, western blot, qRT-PCR and ELISA. Pearson's correlation confirmed a statistically significant negative correlation between IGF-1 and DNMT1. Furthermore, both treatment with 5-Aza-dc and DNMT1-siRNA significantly increased the expression of IGF-1 in HTR8 cells, indicating the potential mechanism of DNMT1-mediated DNA methylation in IGF-1 regulation. However, IGF-1 didn't change DNA methylation or hydroxymethylation. These findings suggest that preeclampsia is associated with hypermethylation of IGF-1 promoter mediated by DNMT1 and provide new insights into the diagnosis and treatment of preeclampsia.

Comprehensive analyses of imprinted differentially methylated regions reveal epigenetic and genetic characteristics in hepatoblastoma

International Nuclear Information System (INIS)

Rumbajan, Janette Mareska; Aoki, Shigehisa; Kohashi, Kenichi; Oda, Yoshinao; Hata, Kenichiro; Saji, Tsutomu; Taguchi, Tomoaki; Tajiri, Tatsuro; Soejima, Hidenobu; Joh, Keiichiro; Maeda, Toshiyuki; Souzaki, Ryota; Mitsui, Kazumasa; Higashimoto, Ken; Nakabayashi, Kazuhiko; Yatsuki, Hitomi; Nishioka, Kenichi; Harada, Ryoko

2013-01-01

Aberrant methylation at imprinted differentially methylated regions (DMRs) in human 11p15.5 has been reported in many tumors including hepatoblastoma. However, the methylation status of imprinted DMRs in imprinted loci scattered through the human genome has not been analyzed yet in any tumors. The methylation statuses of 33 imprinted DMRs were analyzed in 12 hepatoblastomas and adjacent normal liver tissue by MALDI-TOF MS and pyrosequencing. Uniparental disomy (UPD) and copy number abnormalities were investigated with DNA polymorphisms. Among 33 DMRs analyzed, 18 showed aberrant methylation in at least 1 tumor. There was large deviation in the incidence of aberrant methylation among the DMRs. KvDMR1 and IGF2-DMR0 were the most frequently hypomethylated DMRs. INPP5Fv2-DMR and RB1-DMR were hypermethylated with high frequencies. Hypomethylation was observed at certain DMRs not only in tumors but also in a small number of adjacent histologically normal liver tissue, whereas hypermethylation was observed only in tumor samples. The methylation levels of long interspersed nuclear element-1 (LINE-1) did not show large differences between tumor tissue and normal liver controls. Chromosomal abnormalities were also found in some tumors. 11p15.5 and 20q13.3 loci showed the frequent occurrence of both genetic and epigenetic alterations. Our analyses revealed tumor-specific aberrant hypermethylation at some imprinted DMRs in 12 hepatoblastomas with additional suggestion for the possibility of hypomethylation prior to tumor development. Some loci showed both genetic and epigenetic alterations with high frequencies. These findings will aid in understanding the development of hepatoblastoma

Autocrine IGF-1 Action in Adipocytes Controls Systemic IGF-1 Concentrations and Growth

OpenAIRE

Kl?ting, Nora; Koch, Linda; Wunderlich, Thomas; Kern, Matthias; Ruschke, Karen; Krone, Wilhelm; Br?ning, Jens C.; Bl?her, Matthias

2008-01-01

OBJECTIVE?IGF-1 and the IGF-1 receptor (IGF-1R) have been implicated in the regulation of adipocyte differentiation and lipid accumulation in vitro. RESEARCH DESIGN AND METHODS?To investigate the role of IGF-1 receptor in vivo, we have inactivated the Igf-1r gene in adipose tissue (IGF-1RaP2Cre mice) using conditional gene targeting strategies. RESULTS?Conditional IGF-1R inactivation resulted in increased adipose tissue mass with a predominantly increased lipid accumulation in epigonadal fat ...

IGF-1-dependent subunit communication of the IGF-1 holoreceptor: Interactions between αβ heterodimeric receptor halves

International Nuclear Information System (INIS)

Wilden, P.A.; Treadway, J.L.; Morrison, B.D.; Pessin, J.E.

1989-01-01

Examination of 125 I-IGF-1 affinity cross-linking and β-subunit autophosphorylation has indicated that IGF-1 induces a covalent association of isolated αβ heterodimeric IGF-1 receptors into an α 2 β 2 heterotetrameric state, in a similar manner to that observed for the insulin receptor. The formation of the α 2 β 2 heterotetrameric IGF-1 receptor complex from the partially purified αβ heterodimers was time dependent with half-maximal formation in approximately 30 min at saturating IGF-1 concentrations. The IGF-1-dependent association of the partially purified αβ heterodimers into an α 2 β 2 heterotetrameric state was specific for the IGF-1 receptors since IGF-1 was unable to stimulate the protein kinase activity of the purified αβ heterodimeric insulin receptor complex. Incubation of the α 2 β 2 heterotetrameric IGF-1 holoreceptor with the specific sulfhydryl agent iodoacetamide (IAN) did not alter 125 I-IGF-1 binding or IGF-1 stimulation of protein kinase activity. However, IAN treatment of the αβ heterodimeric IGF-1 receptors inhibited the IGF-1 dependent covalent formation of the disulfide-linked α 2 β 2 heterotetrameric complex. These data indicate that IGF-1 induces the covalent association of isolated αβ heterodimeric IGF-1 receptor complexes into a disulfide-linked α 2 β 2 heterotetrameric state whereas Mn/MgATP induces a noncovalent association. Therefore, unlike the insulin receptor in which noncovalent association is sufficient for kinase activation, only the covalent assembly of the IGF-1 receptor αβ heterodimers into the α 2 β 2 heterotetrameric holoreceptor complex is associated with ligand-stimulated protein kinase activation